SFZ63 
442  Z 


Digitized  by  the  Internet  Archive 

in  2007  with  funding  from 

Microsoft  Corporation 


http://www.archive.org/details/buttermakingOOmckarich 


WORKS    OF   PROF.    C.  LARSEN 

PUBLISHED    BY 

JOHN  WILEY  &  SONS,  Inc. 


Exercises  in  Farm  Dairying. 

By  C.  Larsen,  M.S.A.  The  Loose  Leaf  Labo- 
ratory Manual  of  The  Wiley  Technical  Series, 
J.  M.  Jameson,  Editor.  An  Elementary  Man- 
ual for  Agricultural  High  Schools  and  Colleges; 
a  Practical  Guide  for  Farmers  and  Dairymen. 
4to,  paper,  $1.00  net. 

By  McKAY  AND  LARSEN 
Principles  and  Practice  of  Butter-making. 

A  Treatise  on  the  Chemical  and  Physical  Prop- 
erties of  Milk  and  its  Components;  the  Hand- 
ling of  Milk  and  Cream,  and  the  Manufac- 
ture of  Butter  Therefrom.  By  G.  L.  McKay, 
Secretary,  American  Association  of  Creamery 
Butter  Manufacturers,  formerly  Professor  of 
Dairying  in  the  Iowa  State  College,  Ames,  la., 
and  C.  Larsen,  M.S.A.  Third  Edition,  Largely 
Rewritten,  xiv  +  405  pages,  6  by  9.  133 
figures.    Cloth,  $3.00  net. 

By  LARSEN  AND  WHITE 
Dairy  Technology. 

A  Treatise  on  the  City  Milk  Supply,  Milk  as  a 
Food,  Ice  Cream  Making,  By-Products  of  the 
Creamery  and  Cheesery,  Fermented  Milks, 
Condensed  and  Evaporated  Milks,  Milk  Pow- 
der, Renovated  Butter,  and  Oleomargerine.  By 
C.  Larsen,  M.S.A.,  and  Wm.White,  B.S.  xiii  + 
298  pages.  5*  by  8.  4G  figures.  Cloth,  $2.00net. 


PRINCIPLES    AND   PRACTICE 

OF 

BUTTEK-MAKIM 


BY 

G.  L.  McKAY,  Dr.Sc. 

Secretary,  American  Association  of  Creamery  Butter  Manufacturers, 
formerly  Professor  of  Dairying  in  the  Iowa  State  College,  Ames,  la. 

AND 

C.  LARSEN,  M.S.A. 

Professor  of  Dairy  Husbandary,  So.  Dak.,  State  College,  Brookings,  S.  D. 
formerly  Associate  Professor,  Iowa  State  College,  Ames,  la. 


THIRD  EDITION,  LARGELY  REWRITTEN 

TOTAL  ISSUE,   SEVENTEEN   THOUSAND 


NEW  YORK 

JOHN  WILEY  &   SONS,   Inc 

London:  CHAPMAN  &  HALL,  Limited 
1922 


Copyright,  1906,  1908,  1922, 

BY 

G.  L.  McKAY  and  C.   LARSEN 


PRESS   OF 

BRAUNWORTH  4   CO. 

BOOK    MANUFACTURERS 

BROOKLYN,    N.    Y. 


PREFACE   TO   THIRD    EDITION 


The  science  of  dairying  is  constantly  broadening.  The 
methods  and  art  of  manufacturing  the  best  quality  of  butter 
have  gradually  changed  in  conformity  with  the  scientific  prin- 
ciples involved,  and  no  one  should  now  undertake  to  manufac- 
ture butter  until  he  has  made  a  careful  study  of  the  principles 
governing  the  best  methods  of  manufacture . 

The  authors  admit  that,  in  our  present  state  of  knowledge 
and  experimental  progress,  it  is  in  some  instances  difficult  to 
distinguish  well-established  facts  from  those  not  universally 
confirmed;  hence,  it  has  been  their  object  to  give  only  informa- 
tion supported  by  the  preponderance  of  experimental  evidence. 

The  first  and  second  editions  of  this  book  have  been  received 
by  the  dairy  schools  and  the  practical  creamerymen  m  a  manner 
indicating  that  the  work  has  met  with  general  approval.  The 
third  edition  has  been  carefully  revised,  and  additional  chapters 
have  been  added.  The  new  chapters  are:  first,  Defects  Found  in 
Butter — Some  of  the  Causes  and  their  Prevention;  second, 
Neutralization  of  Cream;  third,  Milk  and  its  Products  as  Foods — 
High  Value  of  Milk  Fat;  fourth,  Cold  Storage  and  Butter  for 
Storage  Purposes;  fifth,  New  Tests,  including  Accurate  Method 
of  Determining  Per  Cent  of  Fat  in  Buttermilk,  Skim-milk  and 
Ice  Cream.  The  authors'  endeavor  has  been  to  bring  the  book 
strictly  up  to  date,  and  to  include  the  latest  and  most  approved 
methods  in  dairying. 

The  authors  believe  that  the  subject  of  dairying  should  no 
longer  be  treated  as  a  whole,  and  for  this  reason  have  treated 
special  branches  of  the  subject.  In  this  volume  they  have  en- 
deavored to  give  such  scientific  information  as  relates  to  the 
manufacture  of  butter. 


M* 


IV  PREFACE 

The  scientific  knowledge  embodied  in  the  present  book  has 
been  acquired .  from  time  to  time,  through  work  done  by  various 
investigators  at  different  Experiment  Stations  and  by  leading 
scientists  of  the  Federal  Dairy  Division. 

It  may  be  added  that  the  statistics  and  tables  given  in  this 
work  have  been  quoted  from  noted,  reliable  authorities. 

The  authors  are  indebted  to  the  following  companies  and 

individuals  for  the  use  of  electrotypes:   Cherry  Brothers,  Cedar 

Rapids,  Iowa;   Waterloo  Cream  Separator  Company  and  Iowa 

Separator  Company,  Waterloo,  Iowa;   Vermont  Farm  Machine 

Company,  Bellows  Falls,  Vermont;   Burrell  &  Company,  Little 

Falls,  New  York;  Empire  Cream  Separator  Company  and  Jensen 

Creamery    Machinery    Company,     Bloomfield,     New    Jersey; 

Dairy  Queen  Mfg.  Company,  Flora,  Indiana;   Elyria  Enameled 

Products   Company,    Elyria,    Ohio;     Rice   &  Adams,    Buffalo, 

New  York;  Worcester  Salt  Company,  New  York  City;   Russell 

&  Hastings,  Madison,  Wisconsin;    Louis  F.  Nans,   Creamery 

Package    Company,   Borden   &   Selleck   Company,    De   Laval 

Separator   Company,   Arnold   &    Company,    Diamond    Crystal 

Salt  Company  and  Davis-Watkins  Dairymen's  Mfg.  Company, 

Chicago;    Kirschbraun  &  Sons,  Omaha,  Nebraska;    Professor 

M.  Mortenson,  Ames,  Iowa;    and  Strawberry  Point  Creamery, 

Strawberry  Point,.  Iowa. 

G.  L.  McKay. 
April,  1022.  _    x 

C.  Larsen. 


CONTENTS 


CHAPTER   I 

PAGE 

History  of  Butter-making  and  Composition  of  milk i 

i.  Definition  of  Milk 3 

2.  Composition  of  Milk ' 4 

3.  Variation  of  Total  Solids 5 

4.  Water 6 

5.  Fat  in  Milk 8 

6.  Properties  of  Fat 10 

7.  Glycendes  of  Fat 10 

8.  Condition  of  Fat 11 

9.  Theories  in  Regard  to  Pllms  Enveloping  Fat  Globules 11 

10.  Classes  of  Fats 13 

A .  Volatile 13 

B.  Non-volatile 14 

11.  Composition  of  Butter  Fat 15 

12.  Proteids  (Albuminoids) 16 

A .  Casein 17 

B.  Albumen 18 

13.  Sugar 18 

14.  Ash 19 

15.  Gases  of  Milk ' 20 

16.  Coloring  Matter 22 

17.  Other  Constituents  of  Milk 22 


CHAPTER  II 

Milk  Secretion 23 

1 .  Mammary  Gland  as  a  Secretory  Organ 23 

2.  Internal  Structure  of  Cow's  Udder 23 

3.  Theories  of  Milk  Secretion 26 

4.  Conditions  Affecting  Secretion  of  Milk 28 

5.  External  Appearance  of  Udder ...  30 

6.  Milk  Fever 30 

v 


VI  CONTENTS 

CHAPTER  III 

PAGE 

Properties  of  Milk 32 

1.  Color 32 

2.  Flavor 32 

3.  Opacity  of  Milk 32 

4.  Chemical  Reaction  of  Milk ^ 

5.  Specific  Gravity  of  Milk ^ 

6.  Natural  Separation  of  Milk  and  Cream 35 

7.  Adhesion  of  Milk 37 

8.  Viscosity  of  Milk 37 

9.  Specific  Heat  of  Milk 38 

10.  Effect  of  High  Heating  on  Properties  of  Milk 38 

(1)  Destroys  nearly  all  Germs 39 

(2)  Diminishes  Viscosity  or  Body 39 

(3)  Drives  off  Gases y .  .  .  40 

(4)  Imparts  a  Cooked  Taste 40 

(5)  Precipitates  Albuminoid  and  Ash  Constituents 41 

(6)  Destroys  Properties  of  Enzymes 41 

(7)  Divides  the  Clusters  of  Fat  Globules 42 

(8)  Caramelizes  the  Sugar 42 

General  Remarks 42 

CHAPTER   IV 

Milk  and  Its  Products  as  Foods — High  Value  of  Milk-fat 43 

1.  Chemical  Classification  of  Milk  and  Its  Products  as  Foods 44 

2.  Biological  Classification  of  Foods 45 

A .  Proteins 46 

B.  Ash  or  Mineral  Matter 46 

C.  Two  Unidentified  but  Essential  Food  Substances 47 


CHAPTER   V 

Ferments  in  Milk 54 

1.  Definition 54 

A.  Classification  of  Enzymes 54 

2.  Size  and  Shape  of  Bacteria 55 

3.  Favorable  Conditions  for  Bacterial  Growth 55 

A.  Food 55 

B.  Temperature 56 

C.  Moisture 58 

4.  Unfavorable  Conditions  for  Bacterial  Growth 58 

5.  Kinds  of  Germs  Found  in  Milk 60 

6.  Number  of  Bacteria  in  Milk 62 

7.  Sources  of  Bacteria  in  Milk 62 

8.  Effect  of  Thunder  Storms  on  Souring  Milk 64 


CONTENTS  Vii 
CHAPTER  VI 

PAGE 

Abnormal  Milk 65 

1 .  Colostrum  Milk 65 

2.  Salty  Milk 66 

3.  Bloody  or  Red  Milk 67 

4.  Blue  Milk 68 

5.  Yellow  Milk 68 

6.  Ropy  Milk 68 

7.  Bitter  Milk 69 

8.  Milk  from  Cows  which  Have  Been  in  Milk  a  Long  Period 71 

9.  Milk  from  Spayed  Cows 72 

10.  Milk  from  Sick  Cows 72 

CHAPTER  VII 

Variation  of  Fat  in  Milk  and  Cream 74 

PART  I 

Variation  of  Fat  in  Milk 74 

1 .  Individuality  of  Cows 74 

2.  Breed  of  Cows 75 

3.  Time  between  Milkings 75 

4.  Manner  of  Milking 76 

5.  Fore  and  After  Milk 77 

6.  Age  of  Cow 78 

7.  Advance  in  Lactation 78 

8.  Feed  of  Cows 7g 

9.  Environment 80 

10.  Condition  of  Cow 80 

PART  II 

Variation  of  Fat  in  Cream 81 

1 .  Cream  Screw  Adjustment 82 

2.  Richness  of  Milk 83 

3.  Rate  of  Inflow 85 

4.  Speed  of  Machine 87 

5.  Temperature  of  Milk 88 

6.  Amount  of  Water  or  Skim  Milk  Used  to  Flush  the  Bowl 90 


CHAPTER  VIII 

Receiving,  Sampling,  Grading  and  Testing  Milk  and  Cream 92 

1.  Receiving  and  Grading  of  Milk  and  Cream 92 

A .  Detection  of  Abnormal  Milk  and  Cream  through  the  Senses. .  .  93 

B.  Use  of  Acid  Tests 94 


vin  CONTENTS 


PAGE 

C.  Use  of  Fermentation  Tests 04 

a.  Gerber  and  Wisconsin  Curd  Tests 95 

D.  Grading  Milk  by  Heating 96 

E.  Use  of  Babcock  Test  and  Lactometer 97 

a.  Babcock  Test  of  Milk 08 

b.  Babcock  Test  of  Cream 99 

c.  Does  the  Babcock  Test,  as  Ordinarily  Applied  to  Cream, 

Give  Too  High  a  Reading? ,  100 

d.  Babcock  Test  of  Buttermilk  and  Skim-milk — American 

Association  Test 101 

e.  American  Association  Test .  103 

/.    Determination  of  the  Per  Cent  of  Fat  in  Butter 107 

F.  Sediment  Test 116 

2.  Necessity  of  Good  Milk 117 

3.  Sampling  of  Milk 118 

4.  Sampling  Tube 1 20 

5.  Sampling  Churned  Milk 122 

6.  Frozen  Milk 1 23 

7.  Sour  and  Coagulated  Milk t  ..... ,  ....  .  123 

8.  Apportioning  Skim-milk 124 

9.  Washing  Cans .125 

CHAPTER  LX 

Composite  Samples 127 

1.  Definition 127 

2.  When  to  Sample 127 

3.  Kind  of  Preservatives  to  Add T27 

4.  Arrangement  of  Composite  Samples 128 

5.  Care  of  Composite  Samples 129 

6.  Average  Sample 130 

7.  Composite  Sampling  without  the  Use  of  Preservatives 130 


CHAPTER  X 

Creamery  Calculation 131 

1.  Find  Average  Per  cent  of  Fat 131 

2.  Calculation  of  Overrun 133 

(1)  Thoroughness  of  Skimming 133 

(2)  Completeness  of  Churning. 133 

(3)  General  Losses  in  Creamery 133 

(4)  Composition  of  Butter  Manufactured 133 

3.  Calculation  of  Churn  Yield 135 

4.  What  Should  the  Overrun  in  a  Creanery  Be? 135 

5.  Calculation  of  Dividends t „ 137 

6.  Cream  Raising  Coefficient u 140 

7.  Statement  to  Patrons 140 

8.  Paying  for  Fat  in  Cream  as  Compared  with  Paying  for  Fat  in  Milk.  .  143 


CONTENTS  IX 

CHAPTER  XI 

PAGE 

Heating  Milk  Previous  to  Skimming 145 

1.  Reasons  for  Heating T45 

2.  Advantages  of  Warming  Milk  to  High  Temperature  Previous  to 

Skimming 146 

3.  How  Heated 147 


CHAPTER  XII 

Separation  of  Cream  .  ., 149 

1.  Gravity  Creaming 149 

A .  Shallow-pan  System 149 

B.  Deep-setting  System .' 150 

a.  Probable  Explanation 152 

C.  Water-dilution  Cream  (Hydraulic) 153 

2.  Centrifugal  Creaming 154 

A .  Advantages 155 

B.  History  of  Centrifugal  Separators 155 

C.  Modern  Separators 157 

D.  Classification  of  Separators 158 

E.  Process  of  Separation 158 

F.  Conditions  Affecting  Efficiency  of  Separators 161 

a.  Manner  of  Heating  Milk 161 

b.  Condition  of  the  Milk 163 

c.  Overfeeding  the  Separator 163 

d.  Speed 164 

e.  Steadiness  in  Running 165 

/.   Thickness  of  Cream 165 

g.  Slush  in  Bowl 165 

h.  General  Remarks 166 


CHAPTER   XIII 

Farm  Separators 168 

1.  Introduction  of  Farm  Separators 168 

2.  Reasons  for  Introducing  Farm  Separators 168 

3.  Objections  to  Farm  Separators 171 

4.  Thickness  of  Cream 172 

5.  Power  for  Farm  Separators 174 

6.  Care  of  Cream  on  the  Farm 176 

7.  Disposition  of  Cream 179 

A .  Shipping  of  Cream 180 

B.  Making  Butter  on  the  Farm 180 


CONTENTS 


CHAPTER  XIV 

PAGE 

Neutralization — The  "Neutralization"  of  Cream 183 

1.  Neutralization,  Principle  of 183 

2.  Neutralization  of  Cream  for  Butter-making 184 

3.  The  Preparation  and  Use  of  Lime  as  a  Neutralizer 192 

4.  Pints  of  Lime  Mixture  Required  to  Reduce  Acidity  to  .25  Per  Cent 

(Table) 196 

5.  Other  Neutralizers 199 


CHAPTER  XV 

Pasteurization 201 

1.  Definition 201 

2.  Storch  Test  for  Pasteurization 201 

3.  Pasteurization  Temperatures 202 

4.  Good  Milk  and  Cream  Important 204 

5.  Sanitation  Must  Accompany  Pasteurization 206 

6.  Methods  of  Pasteurization 208 

A .  Flash  or  Instantaneous  Method 208 

B.  Vat  or  Holding  Method 208 

C.  Combined  Flash  and  Holding  Method 208 

7.  Efficiency  of  Pasteurizers 210 

8.  Cost  of  Pasteurization 212 

9.  Disadvantages  of  Pasteurization 214 

10.  Advantages  of  Pasteurization 214 


CHAPTER  XVI 

Cream  Ripening  and  Starters 215 

Cream  Ripening: 

1.  Definition 215 

2.  Objects  of  Ripening 215 

3.  Ripening  Temperature  of  Cream 220 

4.  Amount  of  Starter  to  Add  to  Cream 221 

5.  Mixing  the  Starter  with  the  Cream 221 

6.  Tests  for  Acidity 221 

A .  Mann's  Test 222 

B.  Fanington  Test 223 

7.  Degree  of  Acidity  that  Cream  Should  be  Ripened  to 224 

Starters: 

8.  Definition 225 

9.  History 226 

10.  Classification  of  Starters 226 

11.  Preparation  of  Natural  Starters 226 


CONTENTS  xi 

PAGE 

1 2.  Commercial  Starters  or  Cultures 227 

13.  Preparation  of  Commercial  Starters 230 

14.  Inoculation 232 

15.  Milk  Powder  for  Starters 235 

16.  Length  of  Time  a  Starter  Can  be  Carried .  . 236 

17.  Poor  Starters 236 

18.  Under-ripening  and  Over-ripening  of  Starters 237 

19.  Amount  of  Starter  to  Use 237 

20.  Use  of  Starter-cans 238 


CHAPTER   XVII 

Churning  and  Washing  Butter 239 

1.  Definition 239 

2.  Conditions  Affecting  the  Churnability  of  Cream 240 

A .  Temperature 240 

B.  Influence  of  Length  of  Time  Held  at  Churning  Temperature.  .  .  245 

C.  Richness  of  Cream 245 

D.  Amount  of  Cream  in  Churn 247 

E.  Degree  of  Ripeness 248 

F.  Nature  of  Agitation >  249 

G.  Size  of  Fat  Globules 252 

3.  Straining  of  Cream 253 

4-  Color 253 

5.  When  to  Stop  the  Churning 255 

6.  Churning  Mixed  Sweet  and  Sour  Cream 258 

7.  Difficult  Churning 258 

8.  Keeping  Churn  in  Sweet  Condition 260 

9.  To  Prevent  Butter  from  "Sticking"  to  Churn 262 

10.  Washing  of  Butter 263 

A .  Purpose  of  Washing 263 

B.  Temperature  of  Wash  Water 263 

C.  Kind  of  Wash  Water  to  Use 265 

11.  Methods  of  Purifying  Wash  Water 266 

A .  Filtration 266 

a.  Continuous 269 

b.  Intermittent 270 

B.  Pasteurization 266 

12.  Advantages  of  Purification  of  Wash  Water 271 


CHAPTER  XVIII 

Salting  and  Working  of  Butter , .  272 

1.  Objects  of  Salting .  . ., , . . .   272 

2.  Amount  of  Salt  to  Use  to  Produce  Proper  Flavor 272 

3.  Effects  of  Salt  upon  Keeping  Properties    ,  .  272,  273 


Xll  CONTENTS 

PAGE 

4.  Salt  Facilitates  the  Removal  of  Buttermilk 275 

5.  Salt  in  Relation  to  Water  in  Butter 275 

6.  Kind  and  Condition  of  Salt 277 

7.  Gritty  Butter 278 

8.  Mottled  Butter 279 

9.  Prevention  of  Mottles  in  Butter 284 

10.  Curdy  Specks  in  Butter 285 

11.  Brine  Salting 287 

12.  Salt  Test 288 

A .  Principles  of  the  Test 288 

B.  Chemical  Changes  that  Take  Place 288 

C.  Features  of  Practical  Salt  Tests 289 

D.  To  Make  a  Salt  Test 290 

13.  Working  of  Butter,  Objects  of 291 

14.  Moisture  Tests  of  Butter 293 


CHAPTER  XIX 

Preparing  Butter  for  Market  and  Prevention  of  Mold 294 

1.  Styles  of  Package  and  Kinds  of  Wood  Used 294 

2.  Storing  Butter  in  Creameries 296 

3.  Cost  of  Manufacturing  Butter 297 

4.  Treatment  of  Tubs  and  Boxes 300 

5.  Paraffining  of  Tubs 302 

6.  Paraffining  Tubs  Reduces  Loss  from  Shrinkage 303 

7.  Treatment  of  Parchment  Paper 304 

8.  Yeasts  and  Molds  in  Butter 304 

9.  Mold  on  Butter 306 

A.  Conditions  Favorable  to  Growth  of  Molds 307 

B.  Discolorations 307 

C.  Propagation  of  Molds 307 

D.  Sources  of  Mold  on  Butter 307 


CHAPTER  XX 

The  Composition  of  Butter  and  Factors  that  Influence  its  Control.  . .  309 

1  -  Acts  and  Rulings  as  to  Composition  of  Butter 309 

2.  Compounds  for  Increasing  Yield  of  Butter 310 

3.  Need  for  Regulations 311 

4.  Control  of  Moisture  in  Butter 312 

5.  Analyses  of  Commercial  Butter  between  Thirty  and  Forty  Years  Ago.  315 

6.  Standards  in  Different  Countries 317 

7.  Factors  that  Aid  in  Moisture  Control 318 


CONTENTS  xiii 

CHAPTER  XXI 

PAGE 

Defects  Found  in  Butter — Some  of  the  Causes  and  Their  Prevention  323 

1.  Flat  or  Insipid  Flavor 323 

2.  Stable  Flavors i 324 

3.  Flavors  Acquired  by  Absorption 324 

4.  Cheesy  Flavor 324 

5.  Sour  Flavor 325 

6.  Faulty  Factory  Conditions 325 

7.  Feed  Flavors 327 

8.  Removal  of  Garlic  or  Onion  Flavors 327 

A.  To  Eradicate  Wild  Garlic 328 

9.  Advance  in  Lactation,  Winter  Feeds  and  Stable  Conditions 329 

10.  Tallowy  Flavor 332 

1 1 .  Metallic  Flavors 335 

1 2.  Fishy  Flavor 336 


CHAPTER  XXII 

Judging  and  Grading  Butter 340 

1 .  Standard  for  Judging 340 

2.  Manner  of  Judging 341 

A .  Body 341 

B.  Flavor 341 

C.  Color 341 

D.  Salt 342 

E.  Style 342 

3.  Classification — Grades  and  Scores 342 

A .  New  York  Classif  cation . ; 342 

B.  Chicago  Classification 347 

4.  Export  Butter 350 


CHAPTER  XXIII 

Cold  Storage  and  Butter  for  Storage  Purposes 352 

1.  History  of  Cold  Storage 352 

2.  Mechanical  Refrigeration 353,  363,  375 

3.  Benefits  of  Cold  Storage 353 

4.  Cost  of  Storage 355 

5.  Should  Cold  Storage  Butter  be  Branded? 356 

6.  Butter  for  Storage 357 

7.  Working  and  Packing  Butter  for  Storage  Purposes 360 


xiv  CONTENTS 

CHAPTER  XXIV 

PAGL 

Cooling  Facilities  for  Creameries 362 

1.  Cooling  Systems — Natural  Ice,  Mechanical  Refrigeration  and  Cold 

Water 362 

A .  Natural  Ice  System 365 

a.  Kind  of  Ice  House 365 

b.  Size  and  Shape  of  Ice  House 368 

c.  Filling  the  Ice  House 372 

d.  Source  of  Ice 373 

B.  Use  of  Ice  in  Cooling  Cream 374 

a.  Directly 374 

b.  Indirectly 374 

C.  Mechanical  Refrigeration 375 

a.  Application  in  Creameries 375 

b.  Chemicals  Used  for  Mechanical  Refrigeration.  . 376 

c.  Principles  of  Producing  Cold  Artifu  ially 376 

(1)  Compression 377 

(2)  Condensation 377 

(3)  Expansion 378 

d.  Transferring  the  Cold 378 


CHAPTER  XXV 

Economic  Operation  of  Creamery 381 

1.  Firing  the  Boiler 381 

2.  Burning  Wood  or  Coal 382 

3.  Daily  Weighing  of  Coal  Used 383 

4.  Cleaning  the  Boiler 384 

5.  Priming  of  Boilers 384 

6.  The  Injector 385 

7.  Oil  Separators 385 

8.  Belt,  Pulley  and  Speed  Calculation 385 


APPENDIX 

I.  Legal  Standards  for  Dairy  Products 387 

IT.  Metric  System  of  Weights  and  Measures 388 


BUTTER-MAKING 


CHAPTER  I 

HISTORY     OF     BUTTER-MAKING     AND   COMPOSITION 

OF   MILK 

The  art  of  butter-making  in  some  form  dates  back  to  time 
immemorial.  History  tells  us  that  butter  is  one  of  the  oldest, 
as  well  as  one  of  the  most  universal,  articles  of  diet.  We  are  told 
it  was  used  in  some  form  two  thousand  years  before  the  birth  of 
Christ.  References  are  made  to  it  in  early  Biblical  and  other 
ancient  history.  We  read,  in  Genesis,  that  when  Abraham  was 
visited  by  Angels,  who  appeared  in  the  form  of  men,  "  he  took 
butter  and  milk  and  the  calf  which  he  had  dressed  and  set  it 
before  them."  The  word  "  butter  "  is  mentioned  in  the  Bible 
seven  times.  It  is  known  that  the  Scythians  and  Greeks  used 
butter  in  450  B.C.  A  little  later  there  is  a  record  of  the  Persians 
making  and  using  it.  In  the  early  centuries  butter  was  employed 
in  many  ways.  The  Hindoos  offered  it  as  a  sacrifice  in  their 
worship.  The  Greeks  and  Romans  did  not  eat  it,  but  used  it 
as  a  remedy  for  injuries  to  the  skin.  It  was  considered  by  them 
that  the  soot  of  burned  butter  was  good  for  sore  eyes.  The 
Romans  also  used  it  as  an  ointment  for  the  skin  and  the  hair. 
This  practice  was  common  in  Macedonia,  and  it  is  reported  that 
in  many  cold  regions  persons  use  butter  as  a  bath.  In  Spain,  as 
late  as  the  seventeenth  century,  it  was  found  in  medicine  shops  for 
external  application  only.  In  the  rural  districts  in  Germany, 
fresh  unsalted  butter  has  been  employed  as  a  cooling  salve  for 
burns,  and  has  been  used  to  some  extent  in  this  country. 

In  early  times,  butter  was  not  generally  used  as  a  food,  but 


2  BUTTER-MAKING  AND  COMPOSITION  OF  MILK 

when  it  was  this  was  for  the  purpose  of  enriching  other  foods  in 
cooking.  We  are  told  it  was  stored  in  a  melted  condition,  and 
was  never  eaten  when  fresh. 

In  the  early  methods  of  making  butter,  churning  was  brought 
about  by  agitation  of  whole  milk.  In  our  own  country  at  the 
present  time,  in  some  of  the  Southern  States,  the  method  of  churn- 
ing whole  milk  rather  than  cream  is  still  followed  by  farmers' 
wives.  Some  difference  of  opinion  exists  as  to  the  early  methods 
used  for  creating  agitation  sufficiently  to  gather  butter  from  the 
milk.  Such  methods  were  used  as  placing  the  milk  in  earthen 
vessels  and  beating  it  with  the  hands  until  butter  formed. 
Later,  wooden  stirring  sticks  were  used  for  the  purpose  of  creating 
agitation.  The  Arabs  churned  their  milk  by  placing  it  in  leather 
bags  and  dragging  them  over  the  ground  by  means  of  a  rope 
attached  to  a  horse's  saddle.  Another  method  used  was  that  of 
placing  the  milk  in  skin  bags,  fastening  them  to  a  tree  and 
swinging  them  back  and  forth  to  bring  about  agitation.  (See 
cut,  Chapter  XVII.)  As  time  passed,  more  complete  devices 
or  methods  were  adopted  for  churning,  such  as  the  dash  churn. 
Following  the  dash  churn  came  the  square  box  churn — which  was 
used  extensively  in  creameries  about  twenty  years  ago — and  the 
table  butter  worker.  Now  we  have  the  modern  up-to-date 
combined  churn.  Setting  milk  in  cold  water  and  permitting 
the  cream  to  rise  lessened  the  time  of  churning  and  brought  the 
manufacture  of  butter  down  to  a  science. 

The  adoption  of  the  centrifugal  machine  for  separating 
the  fat  from  the  milk  was  one  of  the  greatest  advancements  in 
butter-making.  (See  cut  of  first  centrifugal  machine  in  Chap- 
ter XII.)  The  first  centrifugal  cream  separator  used  in  Iowa — 
possibly  the  first  used  in  America — was  a  power  separator  which 
Jeppe  Slipsgaard  brought  with  him  from  Denmark  in  1882,  and 
which  was  used  in  a  Danish  community  near  Cedar  Falls,  in 
Black  Hawk  County.  It  is  worthy  of  note  that  this  machine 
was  so  novel  to  the  customs  officers  in  New  York  that  they  held  it 
for  two  months  before  they  could  decide  as  to  whether  it  was 
constructed  of  iron  or  steel.  They  finally  decided  that  it  was  of 
steel  construction  and  fixed  the  duty  at  $93. 


DEFINITION  3 

Marked  improvements  have  been  made  in  the  manufacture 
of  butter  by  the  adoption  of  scientific  methods  and  the  use  of 
modern  equipments.  Changes  have  been  made  in  the  period  of 
lactation.  Formerly  the  cow  furnished  milk  only  for  her  young. 
Through  the  efforts  of  man,  by  breeding  and  selecting,  the  period 
of  lactation  has  been  lengthened  until  at  the  present  time  it 
extends  over  a  period  of  ten  months.  The  cow  at  the  present 
time  is  recognized  as  one  of  the  most  economical  producers  of 
human  food,  hence,  dairying  has  advanced  rapidly  in  all  coun- 
tries that  are  adapted  for  the  production  of  forage  plants  that  are 
suitable  for  feeding  the  cow. 

The  United  States  at  the  present  time  produces  five  times  as 
much  butter  as  any  other  country.  The  late  census  estimates 
863,577,000  pounds  of  factory  butter  manufactured  in  1920  and 
675,000,000  pounds  of  farm  butter. 

Notwithstanding  the  number  of  years  that  butter,  milk  and 
other  dairy  products  have  been  used  for  food,  it  is  less  than  ten 
years  since  the  physiologists  discovered  that  butter  and  milk 
contained  certain  food  elements  that  are  essential  for  the  growth 
of  the  young  that  had  escaped  investigations  made  by  eminent 
chemists.  This  discovery  was  brought  about  by  feeding  experi- 
ments by  such  noted  physiologists  as  Dr.  F.  G.  Hopkins  of  Cam- 
bridge University,  England,  and  Dr.  E.  V.  McCollum  of  Johns 
Hopkins  University  in  this  country.  The  discoveries  made  by 
these  eminent  authorities  will  no  doubt  be  the  means  of  creating  a 
greater  demand  for  dairy  products  of  all  kinds. 

Definition. — Normal  milk  is  a  liquid  secreted  in  special  glands 
of  all  females  belonging  to  the  mammalian  group.  It  is  composed 
chiefly  of  water,  proteids,  fats,  sugar,  and  minerals.  Coloring- 
matters  and  gases  and  some  organic  acids  are  found  in  small 
quantities. 

All  normal  milk  from  the  different  classes  of  animals,  such  as 
mare,  buffalo,  goat,  ewe,  ass,  and  cow,  has  a  general  resemblance 
in  that  it  all  contains  water,  fat,  proteids,  sugar,  and  ash.  But 
milk  from  different  animals  varies  in  the  relative  proportions  of 
its  constituents.  The  chemical  and  physical  properties  are  not 
alike.     When  human  milk  is  treated  with  half  its  volume  of 


4  BUTTER-MAKING  AND  COMPOSITION  OF  MILK 

ammonium  hydrate  and  kept  at  a  temperature  of  6o°  C.  for 
about  twenty  minutes,  it  assumes  an  intense  red  color.  Cow's 
milk  turns  faintly  yellow  if  treated  in  the  same  way.  This  test 
was  reported  by  Unikoff ,  of  St.  Petersburg  (now  Petrograd) ,  at 
the  meeting  of  the  Medical  Section,  Royal  Academy  of  Med- 
icine, in  Ireland.  The  various  kinds  of  milk  also  differ  from 
each  other  in  their  behavior  towards  rennet.  Richmond  has 
divided  milk  into  two  classes:  Class  I  includes  milk  from  the 
ewe,  buffalo,  goat,  and  cow.  When  rennet  is  added  to  the 
milk  from  these  animals,  the  casein  coagulates  into  a  firm  curd. 
Class  II  includes  human  milk,  milk  of  the  ass,  and  mare. 
When  rennet  is  added  to  the  milk  of  these  animals,  a  soft  curd 
or  none  at  all  is  formed.  The  latter  class  seems  to  include  the 
animals  without  horns,  while  the  first  includes  those  with  horns. 

As  the  cow's  milk  is  used  as  a  food  to  a  greater  extent  than 
that  of  any  other  animal,  it  has  been  subjected  to  more  extended 
and  more  careful  investigation,  and,  as  a  consequence,  more 
definite  knowledge  has  been  obtained  concerning  its  composition, 
properties,  and  uses.  The  succeeding  discussions  have  reference 
to  cow's  milk,  if  not  otherwise  stated. 

Composition  of  Milk. — It  is  impossible  to  get  accurate  figures 
on  the  composition  of  milk,  as  each  of  the  milk  constituents  is 
subject  to  fluctuation  from  various  conditions,  such  as  individ- 
uality of  cow,  breed,  season  of  the  year,  stage  of  lactation,  milking 
and  environment. 

The  average  composition,  as  determined  by  280,000  analyses 
reported  by  Richmond  is  as  follows: 

Water 87.35 

Fat 3-75 

Milk-sugar 4 .  70 

Proteids  >  Casein 3-00 


Albumen,  etc 45 

Ash 75 

The  composition  of  various  kinds  of  milk  is  given  by  Konig  as 
follows : 


VARIATION   OF   TOTAL   SOLIDS 


Human 

Mare 

Buffalo 

Ass 

Cow 

Ewe 

Goat 

Sow 

Bitch 

Elephant 

Hippopotamus 

Camel 

Llama 


No.  of 
Analy- 
ses 

Water 

Fat 

Casein 
and  Al- 
bumen 

Milk- 
sugar 

Ash 

107 

87.41 

3-78 

2.29 

6.  21 

•3i 

50 

90.78 

1 .  21 

1.99 

5 

67 

•35 

8 

82.25 

7-5i 

5-05 

4 

44 

•75 

7 

89.64 

1.64 

2.22 

5 

99 

•5i 

793 

87.17 

369 

3-55 

4 

88 

•  71 

32 

80.82 

6.86 

6.52 

4 

9i 

.89 

38 

85-7i 

4.78 

4.29 

4 

46 

.76 

8 

84.04 

4-55 

7-23 

3 

23 

1  05 

28 

75-44 

9-57 

n. 17 

3 

09 

•73 

3 

79 -3o 

9. 10 

2-51 

8 

59 

•50 

1 

90.43 

4-5i 

4 

40 

.11 

3 

86.57 

3-o7 

4 

5 

59 

•77 

3 

86.55 

3-15 

3-9o 

5 

60 

.80 

Specific 
Gravity 


0270 
0347 
0350 
0345 
0316 

0341 

0328 

038 

035 

0313 


1.042 
1  034 


Variation  of  Total  Solids.— As  applied  to  milk,  "  Total 
Solids,"  is  a  term  that  includes  fat,  casein,  albumen,  sugar, 
and  ash;  in  other  words,  all  the  milk  constituents  except  the 
water.  "  Solids  Not  Fat  "  is  a  term  often  used,  and  includes 
the  casein,  albumen,  sugar,  and  ash,  or  all  the  milk  constituents 
except  water  and  fat.  "  Serum  "  is  a  term  used  to  designate  all 
the  milk  constituents  except  the  fat.  The  fat  is  the  most  val- 
uable constituent  of  the  total  solids.  The  variation  in  the  total 
solids  of  milk  during  the  summer  months  is  shown  in  the  table 
quoted  below  from  Dr.  Van  Slyke  of  Geneva,  New  York: 


Month 


May 

June 

July 

August.  .  . 
September 
October . . . 


Per  Cent 
of  Water 


87.44 

8731 

87-52 

87-37 

87 

86.55 


Per  Cent  of 
Total  Solids 


12.56 

12.69 

12.48 

12.63 

13 

13-45 


Dr.  Van  Slyke  also  studied  the  effect  of  the  lactation  period 
upon  the  total  solids  in  milk.     A  herd  of  fifty  cows,  calving  in 


BUTTER-MAKING  AND  COMPOSITION  OF  MILK 


different  months  of  the  year,  was  used  in  the  experiment.  The 
per  cent  of  total  solids  of  this  herd  seems  to  average  a  little  high 
all  through  the  ten  months.  The  total  solids  were  found  to  be 
14  per  cent  during  the  first  month,  decreasing  to  13.47  per  cent 
during  the  next  two  months,  then  gradually  increasing  with  the 
advance  of  the  lactation  period.  In  the  tenth  month  the  average 
total  solids  was  14.83  per  cent.  Pingree,  of  Pennsylvania,  reports 
having  found  normal  milk  from  a  cow  which  contained  17.01 
per  cent  total  solids.  Sherman  1  reports  a  very  high  average 
total  of  the  milk  solids.  He  treated  the  milk  from  thirteen  cows, 
and  found  it  to  contain  on  an  average  18.03  per  cent  of  total 
solids.  Konig  reports  a  minimum  of  total  solids  of  9.31  per  cent, 
a  maximum  of  19.68  per  cent,  and  an  average  of  12.83  P^1"  cent- 
The  average  total  solids  quoted  above  from  Richmond  is  12.65 
per  cent,  which  agrees  closely  with  Konig 's  results. 

The  difference  in  total  solids  of  milk  from  some  of  the  leading 
breeds  has  also  been  studied  by  Dr.  Van  Slyke,  and  the  results 
are  as  follows: 


Breed 


Holstein. . 
Ayrshire. . 
Shorthorn 
Devon..  . 
Guernsey. 
Jersey. . . . 


Per  Cent 
of  Water 


88.20 
87-25 
85-70 
85 .50 
85.10 
84.60 


Per  Cent  of 
Total  Solids 


11.80 
12.7s 
14-30 
14- So 
14.90 
iS-4o 


The  maximum  and  minimum  amounts  of  total  solids  men- 
tioned above  are  abnormal  cases.  The  normal  variations  of 
the  solids  in  milk  are  within  comparatively  narrow  limits.  For 
this  reason  the  minimum  standard  for  total  milk  solids,  in  States 
where  dairy  laws  are  in  force,  is  fixed  by  law.  Usually  12  per 
cent  is  the  minimum. 

Water. — From  what  has  been  said  above  concerning  the  total 
milk  solids,  it  will  be  seen  that  water  constitutes  by  far  the  largest 

1  Jour.  Am.  Chem.  Soc. 


WATER  7 

portion  of  milk.  It  is  quite  uniform,  and  in  milk  from  a  mixed 
herd  the  water  seldom  falls  below  86  per  cent  and  seldom  exceeds 
88  per  cent.  Variations  ranging  from  a  little  less  than  8o  per  cent 
to  a  trifle  over  90  per  cent  are  on  record.  But  such  variations 
must  be  looked  upon  as  occurring  in  only  a  very  few  special  cases. 

It  has  often  been  asserted  that  cows  in  the  spring  of  the  year, 
when  they  are  pasturing  on  new  grass,  or  feeding  on  other  suc- 
culent foods,  yield  milk  which  contains  an  excess  of  water.  Under 
such  conditions  there  is  a  tendency  for  cows  to  produce  milk  with 
a  water  content  a  trifle  higher,  as  has  already  been  shown  by  the 
figures  quoted  from  Dr.  Van  Slyke.  As  a  rule  this  is  much  over- 
estimated. It  is  even  a  common  occurrence  to  hear  creamery 
operators  say  that  their  "  soft  "  or  "  slushy  "  butter,  in  the  early 
spring,  is  due  to  the  excess  of  water  present  in  the  milk.  This 
particular  phase  will  be  discussed  further  under  the  heading  of 
"  Fat  in  Milk." 

The  following  question  has  often  been  raised :  Is  the  water  in 
milk  the  same,  or  any  more  valuable  than  water  obtained  from 
other  natural  sources?  The  water  in  milk,  so  far  as  known,  is 
transuded  from  the  blood-vessels  in  the  udder  into  the  milk 
glands.  It  is  so  perfectly  mixed  with  the  other  milk  constituents, 
and  holds  the  milk  solids  in  such  perfect  emulsion  and  solution 
that  it  would  seemingly  be  impossible  to  prepare  milk  so  per- 
fectly by  artificial  means.  However,  a  substance  is  prepared  by 
Jacob  C.  Van  Marken,  Neuweid,  Germany,  which,  when  added 
to  water,  produces  a  substance  similar  in  appearance  to  watered 
skimmed  milk.  The  preparation  is  named  "  Kalberrahm  Vita." 
The  first  name  literally  means  calf -cream.  It  has  a  syrupy 
consistency,  and  in  appearance  resembles  light-brownish  molasses. 
It  is  sold  in  tin  cans,  and  recommended  highly  for  calf  feeding 
when  mixed  with  skimmed  milk.  When  mixed  with  water,  it  is 
recommended  highly  for  hog-feeding. 

Water  distilled  from  milk  has  the  same  appearance  as  ordi- 
nary distilled  water.  It  is  clear  and  colorless.  The  chemical 
reaction  when  phenolphthalein  is  used  as  an  indicator  is  neutral, 
as  is  that  of  ordinary  distilled  water,  even  when  distilled  from 
milk  in  which  acid  has  developed.     But  there  is  a  considerable 


8  BUTTER-MAKING  AND   COMPOSITION  OF  MILK 

difference  in  the  taste  and  smell.  This  indicates  that  some  of 
the  volatile  substances  are  distilled  over  with  the  water.  The 
probability  is  that  these  flavoring  substances  are  so  closely  asso- 
ciated with  water  in  milk  that  they  are  inseparable,  and  that  the 
only  place  where  this  water  can  be  prepared  so  as  to  assume  these 
qualities  is  in  the  cow's  udder.  The  conclusion  would  then  be 
that  the  water  in  normal  cow's  milk  cannot  be  distilled  and 
replaced  by  natural  water  without  the  loss  of  the  normal  good 
flavor  of  the  product. 

FAT  IN  MILK 

This  is  by  far  the  most  important  constituent  of  milk,  espe- 
cially to  creamery  operators.  It  exists  in  the  milk  in  suspension, 
in  the  form  of  globules  so  small  as  to  be  invisible  to  the  naked  eye. 
Fat  globules,  at  ordinary  living-room  temperature,  are  present  in 
milk  in  a  liquid  form.  Cooling  the  milk  to  a  very  low  tempera- 
ture (about  500  F.)  hardens  them.  When  the  globules  are  caused 
to  unite,  as  in  churning,  they  also  solidify. 

The  size  of  the  fat-globules  is  very  minute,  and  varies  con- 
siderably, according  to  breeds,  individual  cows,  and  the  stage 
in  the  lactation  period.  The  globules  in  the  milk  from  the  same 
cow  also  vary  a  great  deal.  Lloyd  found  fat-globules  in  Jersey 
milk  to  be  from  8  to  1 2  micro-millimeters  in  diameter.  Very  few 
were  less  than  4  micro-millimeters  (a  micro-millimeter  is  io^o 
millimeter,  or  25000  of  an  inch) .  The  majority  of  the  fat-globules 
in  milk  from  Shorthorn  cows  measured  from  6  to  8  micro- 
millimeters  in  diameter.  According  to  Fleischmann,  the  size  of 
fat-globules  varies  between  1.6  micro-millimeters  and  10  micro- 
millimeters  in  diameter.  A  Danish  investigator  maintains  that 
the  diameter  of  fat-globules  is  between  .0063  and  .00014  milli- 
meter, and  that  1  cubic  centimeter  of  milk  contains  from  2.6  to 
1 1.7  million  globules.  He  also  asserts  that  a  reflection  of  the 
light  renders  it  very  difficult  to  get  the  proper  size  of  the  fat- 
globules,  as  the  light  tends  to  make  the  globules  appear  larger 
than  they  are  in  reality. 

It  has  been  maintained  by  some  that  the  larger  fat-globules 
contain  fats  which  are  different  from  those  contained  in  the 


FAT  IN  MILK 


9 


smaller  globules.     But  this  is  by  some  investigators  considered 
to  be  a  matter  of  conjecture.     Most  authorities  now  believe 


a. 

Skim  milk 

o     „    o 

o 

» 

u     O 

o  °.°     0 

• 

•  *• 

0 

°o  • 

O 

o 

• 

O 

•  « 

o 

o      • 

• 
« 

°;  ° 

o 

o 

o 

e 
• 

0 

Q>° 

o 

*    o 

6 

m> 

•  0 

oo 
o 

0 

•    • 

•     * 

0 

o 

o 

o 

o   • 

• 

8%'    o 

• 

o 

•  ° 

• 

»• 

• 

o 

O      o° 

o 

O 

„v 

o.o 
Vop 

o 

6.  Milk. 


arc 


-obp&9£«s 


tPch>Jnty>.°0°.°o<> 


<t.  Cream. 

jStVfC. 

<£  Colostrum. 


Fig.  i. — Microscopical  appearance  of  different    kinds  of  milk.      Magnified  300 
times.     (U.  S.  Farmers'  Bui.  No.  42.) 


that  there  is  no  difference  in  the  kinds  of  fat  of  the  different-sized 

globules,  even  though  some  experiments  1  show  that  fat  composed 

1  Gembloux,  Belgium,  Creamery  Jour.,  London,  No.  8,  Vol.  I. 


10  BUTTER-MAKING  AND  COMPOSITION  OF  MILK 

of  larger  globules  has  a  finer  flavor,  and  a  little  more  oily  appear- 
ance. 

From  what  has  been  said,  it  will  be  seen  that  the  minute- 
ness of  the  fat-globules  is  almost  inconceivable.  They  were 
first  discovered  in  1697  by  A.  von  Leeuwenhoek.  The  minute 
state  of  division,  or  the  form  of  emulsion  in  which  they  exist 
in  milk,  renders  it  easy  to  digest  when  consumed  as  a  food. 

Properties  of  Fat. — The  specific  gravity  of  pure  butter-fat 
at  1 50  C.  is  .93002.  The  refractive  index  of  butter-fat  at  220  C.  is 
on  an  average  1.459.  The  melting-point  of  pure  butter-fat,  as 
now  determined,  varies  between  320  and  370  C.  (900  F.  and 
99°  F.) 

When  pure  butter-fat  is  rapidly  cooled,  it  solidifies  into  one 
solid  mass;  but  if  allowed  to  cool  gradually,  part  of  it  solidifies, 
and  part  of  it  remains  a  liquid  longer  than  other  parts.  This 
seems  to  indicate  that  some  fats  with  a  high  melting-point  sepa- 
rate out  from  the  fats  with  a  low  melting-point.  This  behavior 
of  pure  butter-fat  is  not  well  understood,  as  it  contradicts  the 
now  accepted  theory  that  the  different  fats  are  in  chemical  com- 
bination with  each  other,  rather  than  a  mechanical  mixture  of 
different  glycerides  of  fat. 

Glycerides  of  Fat. — By  this  term  we  understand  that  the 
fatty  acid  radicals  are  in  chemical  combination  with  the  glycerol 
(glycerine)  radical,  thus: 

Fatty  acid  radicals. 
Glycerol  radical.   [  C4H7O2         (Butyric) 

C3H5     C18H3302     (Oleic) 
C18H35O2     (Stearic) 

The  chemical  formula  for  glycerine  is : 


Glycerol  radical. 
C3H5 


Hydroxy  1  groups. 

OH 
OH 
OH 


The  difference  and  similarity  of  these  two  formulas  are 
easily  observed,  and  the  reason  why  the  term  "  Glyceride  of  Fat  " 
has  been  applied  to  such  a  compound  is  evident. 


CONDITION  OF  FAT  11 

Condition  of  Fat. — Whether  the  fats  in  milk  exist  in  chemical 
combination,  or  whether  they  exist  as  glyceride  of  butyrin, 
stearin,  olein,  etc.,  in  the  form  of  a  mechanical  mixture,  is  a 
question  in  dispute.  If  they  exist  in  the  latter  form,  the  composi- 
tion of  the  different  fats  must  be  as  follows : 


Butyrin.  Olein.  Stearin. 


C3H. 


(  C4H7O2 
C4H7O2        C3H1 
C4H7O2 


C18H33O2 
C18H33O2     C3H5 

C]8H3302 


C18H35O2 

Ci8H3502,etc. 

C]8H3s02 


and  the  total  fat  made  up  of  a  mechanical  mixture  of  these  and 
the  remainder  of  the  fats  in  butter-fat. 

Richmond  and  other  authors  believe  that  fat  probably  exists 
in  milk  chemically,  as  first  mentioned  and  illustrated;  because, 
if  the  fat  were  a  mixture  of  glycerine  tributyrate  with  other 
glycerides  of  fat,  butyrin  or  glycerol  tributyrate  could  be  dis- 
solved out  by  the  use  of  alcohol.  But  this  is  not  the  case.  More- 
over, if  butyrin  existed  separately  in  milk,  it  would  be  possible 
to  distill  it  off  under  reduced  pressure.     This  cannot  be  done. 

Theory  in  Regard  to  Films  Enveloping  Fat-globules. — The 
extreme  minuteness  of  the  fat-globules  in  milk  renders  it  almost 
impossible  to  determine  by  direct  microscopical  observation 
whether  there  is  a  membrane  around  each  globule  or  not.  Fleisch- 
mann  and  Lloyd  assert  that,  so  far  as  they  were  able  to  detect, 
there  is  no  real  membrane  surrounding  each  globule. 

The  theory  generally  accepted  in  the  past  was  that  the  film 
surrounding  the  fat-globules  was  simply  due  to  surface  tension, 
or  to  the  fact  that  the  molecules  of  the  fat  have  a  greater  attrac- 
tion for  themselves  than  they  have  for  the  molecules  of  the  serum 
in  which  they  are  held  in  suspension.  In  support  of  this  two 
arguments  are  advanced. 

(1)  The  natural  milk-fat  may  be  removed  from  milk  and 
artificial  fat  substituted  in  its  place.  The  resultant  milk  has 
characteristics  similar  to  milk  containing  normal  fat,  that  is,  the 
emulsion  which  milk  forms  with  the  artificial  fat  is  apparently 
like  that  formed  with  the  natural  fat. 

(2)  If  there  were  a  special  albuminous  membrane  around 


12  BUTTER-MAKING  AND  COMPOSITION  OF  MILK 

each  fat-globule,  cream  should  contain  a  higher  percentage  of 
albuminoids  than  milk.     This,  Richmond  maintains,  is  not  so. 

Dr.  S torch  concludes  from  extensive  researches  that  there  is  a 
gelatinous  membrane  enveloping  the  fat-globules.  His  conclu- 
sions are  based  mainly  upon  the  first  three  reasons  given  below. 
The  other  facts  mentioned  also  support  his  conclusions : 

(i)  When  milk  has  been  stained  with  ammoniacal  picro- 
carmine,  and  the  cream  washed  with  water  until  it  is  free  from 
milk-sugar,    a   stained   layer   is   present   around   each   globule. 

(2)  He  has  succeeded  in  isolating  this  gelatinous  substance 
from  cream  and  butter.  Owing  to  its  existence  in  these  two 
substances,  he  assumes  that  it  is  also  present  in  milk. 

(3)  When  ether  is  added  to  milk,  the  fat-globules  ..dissolve 
with  difficulty,  unless  some  alkali  is  added  to  the  milk  first. 

(4)  Bichamp  maintains  that  when  ether  is  added  to  milk 
the  fat-globules  are  enlarged  due  to  the  ether  passing  through  the 
supposed  membrane  by  the  process  of  osmosis.  He  considers 
this  fact  sufficient  to  prove  that  there  is  a  membrane  encircling 
each  globule. 

(5)  Butter  containing  85  to  86  per  cent  fat  is  asserted  by 
Richmond  to  have  the  same  consistency  as  cream  containing 
about  72  per  cent  fat  at  the  same  temperature.  The  solidity  of 
butter  is  due  to  the  close  proximity  of  the  fat-globules.  Now,  if 
cream  with  less  fat  has  the  same  consistency  as  butter,  the  prox- 
imity of  the  fat-globules  must  be  equal  to  that  of  the  butter; 
this  would  indicate  that  there  is  a  membrane  and  that  this  mem- 
brane increases  the  size  of  the  fat-globules. 

(6)  The  fact  that  cream  separated  by  centrifugal  force  is 
more  easily  churned  than  cream  of  the  same  richness  separated 
by  gravity  methods,  would  also  be  explained  if  the  fat-globules  in 
milk  had  such  a  membrane  surrounding  them. 

This  membrane,  or  what  is  believed  to  be  a  membrane, 
Storch  has  isolated  and  analyzed.  He  finds  it  to  consist  of 
94  per  cent  of  water  and  6  per  cent  of  proteid. 

The  reasons  deduced  by  Storch  are  strong;  and  the  behavior 
of  cream  and  butter  renders  it  probable  that  there  is  such  a 
membrane  enveloping  each  globule  of  fat. 


CLASSES  OF  FATS  13 


CLASSES  OF  FATS 


There  are  two  great  classes  or  groups  of  fats  present  in  the_ 
butter,  namely : 

(i)  Volatile  and  Soluble, 

(2)  Non- volatile  and  Insoluble. 

It  was  previously  stated  that  little  is  known  concerning  the 
way  in  which  the  fatty  acids  are  combined  with  glycerine  in  the 
milk;  but,  for  the  sake  of  convenience,  the  fats  will  be  referred 
to  as  if  they  existed  as  separate  glycerides  of  fat. 

The  terms  "  Volatile  "  and  "  Non- volatile  "  are  applied  to 
the  glycerides  of  fat,  or  to  the  fats  as  they  exist  in  butter.  Strictly 
speaking,  this  is  not  proper,  as  they  do  not  assume  the  volatile 
characteristics  until  the  glycerine  separates  from  the  fatty  acids; 
it  is  only  then  that  the  latter  become  volatile. 

Volatile  Fats. — The  first  group,  or  the  volatile  fats,  include 
butyrin,  caproin,  caprylin,  caprin,  and  laurin.  Butyrin  is  the 
one  present  in  the  largest  proportion.  Laurin  and  caprin  are 
partially  non-volatile.  Butyrin  is  the  most  important  fat 
belonging  to  the  volatile  group.  It  is  the  most  important  quan- 
titatively and  also  qualitatively.  So  far  as  is  known,  butyrin 
is  the  least  stable  of  any  of  the  butter-fats.  Under  normal  con- 
ditions, so  long  as  the  fatty  acid  remains  in  combination  with  the 
glycerol,  it  is  neither  volatile  nor  soluble  in  water;  but  as  soon 
as  separation  takes  place,  due  to  the  action  of  micro-organisms, 
or  to  the  effect  of  light  and  air,  it  becomes  volatile,  and  escapes 
in  the  form  of  gas. 

It  is  also  claimed  that  these  volatile  fats  have  the  special 
properties  of  absorbing  odors  and  gases  to  a  greater  extent  than 
any  of  the  other  fats.  This  absorption  takes  place  when  fat 
comes  into  contact  with  the  undesirable  taints.  For  this  reason 
it  is  essential  that  milk,  cream  or  butter  be  kept  away  from  any 
foreign,  undesirable  odors.  These  taints  may  also  be  imparted 
to  the  fat  before  the  milk  is  drawn.  If  the  cow  is  fed  on  unde- 
sirable food,  such  as  turnips,  onions,  garlic,  etc.,  the  milk  from  the 
cow  assumes  undesirable  characteristic  flavors  which  can  easily  be 
recognized  in  the  finished  product.     On  the  other  hand,  such 


14  BUTTER-MAKING  AND  COMPOSITION  OF  MILK 

foods  as  well-cured  clover  hay  and  bran  seem  to  impart  desirable 
flavors  to  milk  and  butter. 

The  presence  of  these  volatile  fats  in  butter  is  quite  uniform, 
and  is  a  distinguishing  feature  of  pure  butter-fat.  The  detection 
of  adulteration  of  butter  with  foreign  fats  is  based  chiefly  upon 
the  presence  of  these  volatile  fats.  The  characteristic  desirable 
flavor  of  butter  is  also  believed  to  be  due  to  the  presence  of  the 
volatile  fats.  The  volatile  fats  vary  but  slightly  during  the  dif- 
ferent seasons  of  the  year.  They  are  present  in  the  greatest 
proportion  during  the  spring  and  early  summer  months,  when 
cows  are  fed  on  grass,  and  also  during  the  early  stage  of  the  period 
of  lactation.  They  decrease  gradually  as  the  lactation  period 
advances.  , 

Volatile  fats  comprise  about  8  per  cent  of  the  total  fats  in 
milk. 

Non- volatile  Fats. — This  group  constitutes  about  92  per  cent 
of  the  total  fats  in  butter.  Chemists  now  agree  that  palmitin, 
stearin,  olein,  and  myristin  are  the  most  important  ones  to  be 
considered,  as  will  be  seen  from  the  table  quoted  from  Richmond. 

These  non- volatile  fats  are  of  special  importance,  as  the 
relative  amount  of  each  of  these  fats  largely  causes  the  variation 
in  the  hardness  and  softness  of  the  butter  and  butter-fat.  The 
melting-point  of  these  different  fats  varies  according  to  the  dif- 
ferent investigators :  olein  is  a  liquid  at  ordinary  temperatures  and 
melts  at  about  41  °  F.;  stearin,  on  the  other  hand,  has  a  melting- 
point  of  about  1500  F.;  palmitin  also  has  a  high  melting-point, 
namely,  about  1420  F.;  myristin  melts  at  about  1290  F. 

Olein  has  been  found  to  be  present  in  the  greatest  propor- 
tion during  the  spring,  when  cows  are  fed  on  grass.  When 
cows  are  fed  on  normal  dry  food,  as  in  the  winter  time,  it  is  present 
in  a  much  less  degree.  This,  together  with  the  small  increase  of 
volatile  fats,  is  the  cause  of  the  softer  butter  so  frequent  in  the 
spring.  The  hardness  of  the  butter  in  the  fall  or  winter  is  due 
chiefly  to  the  presence  of  a  slightly  increased  amount  of  the  fats, 
with  a  high  melting-point,  as  mentioned  above. 

From  what  has  been  said  above,  one  is  led  to  believe  that, 
by  melting  a  sample  of  butter  which  contains  these  different 


COMPOSITION  OF  BUTTER-FAT 


15 


fats,  the  fats  with  a  low  melting-point  would  melt  first,  and  leave 
the  remainder  in  an  unmelted  condition.  Such  is  not  the  case. 
Butter-fat  in  this  respect  behaves  a  good  deal  like  different 
metals  with  different  fusing-points.  When  they  are  melted  and 
mixed  together,  cooled  and  then  remelted  they  assume  a  common 
melting-point.  Butter-fat  behaves  in  the  same  way.  It  melts 
at  a  temperature  of  91  °  to  96  °  F. 

As  the  body  temperature  of  cows  (about  1010  F.)  is  above  this 
temperature,  the  fat  globules  are  present  in  the  milk  in  liquid 
form  when  it  is  first  drawn.  A  peculiarity  about  these  fat- 
globules  in  milk  is  that  the  milk  and  fat  may  be  cooled  below  the 
melting-point  of  the  fat  of  butter  without  the  fat-globules  in  milk 
being  solidified.  It  requires  a  temperature  of  between  6o°  and 
780  F.  before  the  fat-globules  in  milk  begin  to  solidify.  When 
these  small  fat-globules  are  caused  to  unite,  as  during  the  churning 
process,  they  solidify  at  a  higher  temperature.  This  behavior  of 
the  fat  in  milk  evidently  must  be  due  to  a  relative  change  in  the 
position  of  the  molecules  of  fat  during  the  process  of  cooling  and 
warming.  No  definite  explanations,  so  far  as  is  known,  have  been 
given  for  this  condition  of  the  fat. 

The  non-volatile  fats  found  in  butter-fat  are  practically  the 
same  as  those  found  in  other  animal  fats. 

Composition  of  Butter-fat. — In  his  "  Dairy  Chemistry," 
Richmond  gives  the  following  composition  of  butter-fat,  repre- 
senting the  mean  results  obtained  by  different  observers: 


Fat 


8  per  cent  volatile. 


92  per  cent  non-volatile. 


Per  Cent 

r  Butyrin 3 .  85 

\  Caproin 3 .  60 

ICaprylin 55 

'  Caprin 1.9 

Laurin 7.4 

Myristin 20 .  2 

Palmitin 25.7 

Stearin 1.8 

Olein 35 


Richmond  also  gives  the  percentage  of  glycerine  and  fatty 
acids  in  each  of  the  different  fats,  as  follows: 


16 


BUTTER-MAKING  AND   COMPOSITION  OF  MILK 


Butyrin 3.85%  yielding 

Caproin 3.60  yielding 

Caprylin 55  yielding 

Caprin 1 .9  yielding 

Laurin 7.4  yielding 

Myristin 20.2  yielding 

Palmitin 25.7  yielding 

Stearin 1.8  yielding 

Olein 35  yielding 


94.84 


and  1.17%  glycerine 
and  .86  glycerine 
glycerine 
glycerine 
glycerine 
glycerine 
glycerine 
glycerine 
glycerine 

12.53 


PROTEIDS  (ALBUMINOIDS) 

The  proteids  of  milk  are  present  partly  in  solution  and 
partly  in  suspension.  They  are  present  in  a  very  complex 
chemical  form.  Some  of  the  chemists  reckon  as  many  as  eight 
different  albuminoids  or  proteids  in  milk.  Duclaux  claims  that 
there  are  only  two  kinds  of  albuminoids,  the  coagulable  and  non- 
coagulable  casein.  He  has,  by  the  use  of  a  fine  filter,  been  able  to 
separate  the  fat  and  the  coagulable  from  the  rest  of  the  serum. 
The  amount  of  coagulable  casein  is  claimed  to  vary  considerably, 
and  seems  to  depend  upon  the  amount  of  lime  phosphate  present. 
The  filtrate  which  Duclaux  obtained  from  filtering  the  milk  was 
clear  and  colorless,  which  proves  that  the  removal  of  the  casein 
was  quite  complete.  In  order  to  remove  casein  from  milk,  a 
special  filter  (Chamberland)  is  employed.  Owing  to  this  fact, 
we  may  consider  the  casein  to  be  present  in  suspension  or  semi- 
solution.  Noted  chemists,  such  as  Babcock,  Van  Slyke,  Duclaux, 
Storch,  Hammarsten,  Ritthausen,  and  Richmond,  disagree  upon 
the  number  of  albuminoid  substances  found  in  milk,  and  upon  the 
chemical  behavior  of  each. 

For  all  practical  purposes  it  is  safe  to  mention  two,  namely, 
(1)  casein,  and  (2)  albumen.  Those  two  substances,  as  all  agree, 
are  present  in  milk,  and  constitute  practically  all  the  albuminoids 
in  milk.  But  after  these  two  have  been  separated  from  milk  a 
slight  precipitation  can  be  obtained  by  treating  the  filtrate  with 
alcohol.  This  has  been  called  albumose  and  also  lactoglobulin. 
From  this  resultant  filtrate  a  very  small  amount  of  material 
containing    nitrogen    can   again    be    separated.     Dr.    Babcock 


CASEIN  17 

has  obtained  a  substance  from  milk  called  fibrin.  These 
latter  substances,  however,  are  present  in  minute  portions,  and 
are  believed  by  some  of  the  best  scientists  to  be  the  same  as  the 
albumen.  Their  presence  in  the  filtrate  is  due  to  incomplete 
precipitation  of  the  albumen  in  the  first  place. 

Casein. — Casein  is  by  far  the  most  important  of  all  of  the 
albuminoids.  It  is  the  substance  which  forms  the  curd  in  cheese- 
making.  In  fresh  milk,  as  is  now  understood,  it  is  in  chemical 
combination  with  lime  salts.  It  is  on  this  account  that  fresh  milk 
shows  the  amphoteric  reaction,  which  will  be  explained  under 
the  "  Properties  of  Milk."  The  coagulation  of  casein  by  the 
addition  of  rennet  or  dilute  acids  is  thought  to  be  due  to  this 
union  between  the  casein  and  lime.  Fleischmann  refers  to  this 
as  the  "  caseous  matter  "  of  milk.  The  viscosity  of  normal  milk 
is  believed  to  be  due  in  a  large  measure  to  this  condition  of  casein 
in  milk.  It  causes  the  casein  to  be  present  in  a  colloidal  condi- 
tion. When  milk  coagulates  by  natural  or  by  artificial  means, 
the  union  between  the  casein  and  lime  phosphate  is  largely 
broken. 

Casein  and  albumen  differ  in  composition,  in  that  the  casein 
contains  phsophorus  and  less  sulphur  than  does  albumen. 
Fleischmann  maintains  that  a  substance  called  nuclein  is  asso- 
ciated with  casein,  and  is  not  found  in  albumen. 

Casein  is  precipitated  by  the  use  of  rennet  and  dilute  acids, 
and  coagulates  spontaneously,  due  to  the  acid  formed  in  the  milk. 
The  precipitates  formed  by  the  use  of  different  precipitating 
agents  are  not  alike.  The  curd  coagulated  by  rennet  contains 
more  fat  and  calcium  phosphate  than  the  curd  which  is  precip- 
itated by  dilute  acid  or  by  the  spontaneous  souring  of  the  milk.  If 
milk  stands  at  air  temperature  for  any  length  of  time  after  milk- 
ing, the  caseous  matter  (or  the  nitrogenous  matter  combined  with 
lime)  tends  to  separate.  The  caseous  matter  of  milk  is  not  com- 
pletely precipitated  by  heat,  although  heat  partially  destroys  the 
union  between  the  casein  and  lime.  This  largely  destroys  the 
action  of  rennet.  Instead  of  getting  a  smooth  solid  coagulum,  a 
more  flaky  precipitate  is  obtained.  For  this  reason  milk  for 
cheese-making  should  not  be  heated  to  a  high  temperature.     By 


18  BUTTER-MAKING  AND  COMPOSITION  OF  MILK 

heating  milk  in  a  glass  flask  to  a  high  temperature,  and  letting  it 
stand  for  a  time,  it  will  be  found  that  a  mineral  precipitate  has 
settled  to  the  bottom.  This  precipitate  is  believed  to  be  a  lime 
phosphate,  which,  previous  to  heating,  was  combined  with  the 
casein  of  the  milk.  By  adding  calcium  chloride  (CaCy  to  milk 
which  has  been  heated,  its  normal  condition  towards  the  action  of 
rennet  is  again  restored. 

Albumen. — If  the  casein  is  removed  from  the  milk  by  pre- 
cipitation, and  then  filtered  off,  the  nitrate  will  contain  a  sub- 
stance which  will  precipitate  when  boiled.  This  is  albumen, 
and  is  similar  in  character  to  albumen  from  the  white  of  an 
egg.  It  differs  from  casein  in  that  it  is  not  precipitated  by 
rennet  or  acids,  but  precipitates  on  heating.  It  does  not  contain 
any  phosphates,  but  contains  a  comparatively  large  amount  of 
sulphur. 

As  the  albumen  is  soluble  in  rennet  and  dilute  acids,  it  can 
readily  be  seen  that  it  is  retained  in  the  whey  obtained  in  cheese- 
making.  When  albumen  is  present  in  small  quantities,  as  it  is  in 
normal  milk,  heating  does  not  completely  precipitate  it,  unless 
the  casein  or  curd  is  first  removed.  If,  on  the  other  hand, 
albumen  is  present  in  excess,  as  is  the  case  in  colostrum,  the  major 
portion  of  the  albumen  is  precipitated  when  heat  is  applied  with- 
out first  removing  the  casein. 

Sugar. — Milk-sugar  occurs  in  milk  to  the  extent  of  about  5 
per  cent.  It  varies  very  little  in  quantity,  seldom  falling  below 
3i  per  cent  and  seldom  rising  above  5!  per  cent.  It  occurs  in 
solution,  and  is  not  found  elsewhere  in  nature. 

Milk-sugar  is  the  most  unstable  component  of  milk;  its 
decomposition  is  brought  about  quickly  and  easily  by  the  action 
of  micro-organisms.  If  these  could  be  entirely  excluded  from  the 
milk,  it  would  keep  for  an  almost  indefinite  length  of  time.  As  it 
is  impossible  under  practical  conditions  to  entirely  exclude 
organisms  from  the  milk,  the  only  way  to  retard  and  prevent  the 
growth  of  germs  and  thereby  prevent  the  changing  of  the  sugar 
into  other  products,  is  to  cool  the  milk  to  a  low  temperature 
(500  F.),  or  to  heat  the  milk  to  a  sufficiently  high  temperature 
(1800  F.)  to  destroy  most  of  the  germs.     According  to  Van  Slyke 


ASH  19 

and  Hart,  the  decomposition  of  the  caseous  matter  produces  free 
casein.  When  about  .5  per  cent  acid  has  developed  in  the  milk, 
the  free  casein  combines  with  the  acid  and  forms  casein  lactate. 
The  chemical  composition  of  milk-sugar  is  C12H22O11+H2O. 
Were  a  perfect  decomposition  of  milk-sugar  into  lactic  acid  to 
take  place,  the  following  equation  would  represent  the  change: 

(Milk-sugar)     (Lactic  acid) 

C12H24O12  =  4C3He03. 

Such  an  ideal  change,  however,  never  takes  place.  In  such  a 
case,  one  gram  of  milk-sugar  should  produce  one  gram  of  lactic 
acid.  In  a  number  of  experiments  carried  on  by  one  of  the 
authors  of  "  The  Analysis  of  Cream  during  Different  Ripening 
Stages,"1  the  highest  amount  of  acid  produced  from  one  gram  of 
milk-sugar  was  .8  of  a  gram.  This  indicates  that  there  are 
always  accompanying  by-products  produced,  besides  lactic 
acid,  when  milk-sugar  is  being  decomposed  in  cream  or  milk. 
The  sourness  of  milk  is  due  to  this  change.  The  by-products 
which  accompany  the  production  of  lactic  acid  are  many 
and  various.  The  most  important  ones  are  gases  of  different 
kinds,  such  as  carbonic  acid  gas  (CO2);  marsh  gas  (CH4); 
hydrogen  (H);  and  nitrogen  (N.)  Small  amounts  of  alcohol, 
formic,  acetic,  and  succinic  acids  are  said  to  be  normal 
accompanying  by-products  also.  These  by-products  may  also 
partially  result  from  the  breaking  down  of  some  of  the  other  milk 
components. 

As  milk-sugar  is  in  perfect  solution,  it  follows  the  water  of 
milk,  and  in  cheese-making  nearly  all  of  it  passes  into  the 
whey.  Commercially  and  chemically  it  is  prepared  from  whey. 
It  is  a  white,  not  very  sweet  powder,  and  is  used  for  medicinal 
purposes  to  dilute  pure,  powerful  drugs.  It  is  also  used  exten- 
sively in  the  preparation  of  modified  milk. 

Ash. — The  ash  of  milk  is  present  in  very  small  quantities, 
and  when  viewed  from  such  a  standpoint  it  may  first  seem  to  be  of 
small  importance.     On  account  of  the  effect  of  the  mineral  con- 

1  Thesis,  I.  S.  C,  Ames,  la. 


20  BUTTER-MAKING  AND  COMPOSITION  OF  MILK 

stituents  upon  the  properties  of  milk,  it  is  one  of  the  most  impor- 
tant components  of  the  milk.  It  exists  partly  in  solution,  and 
partly  in  suspension.  Babcock  maintains  that  about  one-third 
of  the  usual  ash  constituents  are  in  suspension,  and  that  they 
consist  chiefly  of  lime  phosphate. 

All  of  the  minerals  in  milk  consist  chiefly  of  potash,  lime, 
soda,  magnesia,  and  iron,  combined  with  phosphoric,  hydro- 
chloric, sulphuric,  and  carbonic  acid.  Calcium  phosphate 
constitutes  about  one-half  of  all  the  ash  constituents.  They 
are  named  above,  in  order,  according  to  the  extent  to  which 
they  occur  in  milk. 

Gases  of  Milk. — These  do  not  normally  exist  in  milk  to  such 
an  extent  as  to  enable  chemists  to  determine  them  quantita- 
tively, but  they  are  of  great  importance,  owing  to  the  effect  they 
have  upon  the  quality  of  the  milk,  viewed  in  the  commercial 
sense. 

Gases  in  milk  may  be  divided  into  two  classes  according  to 
their  origin;  namely,  (i)  those  imparted  to  milk  before  milking 
and  (2)  those  which  are  later  formed  and  absorbed  in  milk. 

(1)  When  freshly  drawn,  milk  has  a  characteristic  odor, 
which  seems  to  be  normal  to  all  fresh  milk.  The  gases  which 
cause  this  odor  are  very  volatile,  and  by  cooling  and  stirring  the 
milk  can,  to  a  large  extent,  be  eliminated.  The  amount  and 
kind  of  taints  existing  in  milk,  immediately  after  it  has  been 
drawn,  largely  depend  upon  the  food  which  the  cow  has  been 
fed.  Turnips,  onions,  and  garlic,  when  fed  to  cows  a  short  time 
before  milking,  cause  undesirable  gases  or  taints  to  exist  in  the 
milk.  Good  hay,  bran,  and  good  grass  produce  milk  of  superior 
quality,  containing  no  odors  excepting  those  which  are  natural  to 
all  milk  when  first  drawn. 

The  milk  yielded  by  cows  pasturing  in  the  Alps  of  Switzer- 
land is  said  by  tourists  to  possess  a  peculiar,  not  undesirable, 
spicy  odor  and  flavor.  It  is  maintained  by  the  native  people  in 
Switzerland  that  the  peculiar  flavor  of  the  Emmenthaler  cheese 
cannot  be  developed  anywhere  else  in  the  world.  This  flavor 
they  believe  to  be  due  to  the  kind  of  vegetation  the  cows  feed 
upon  in  the  Alpine  pastures.     In    Denmark,  the    poor  people 


GASES  OF  MILK  21 

who  do  not  own  much  land,  graze  their  cows  along  the  roads 
where  weeds  of  different  kinds  grow.  Milk  from  such  cows  has  a 
peculiar  characteristic  odor  or  taint.  In  this  country  it-is  ~a 
common  occurrence  to  find  that  milk  delivered  by  patrons  who 
keep  their  cows  on  timber-land  pastures  has  a  peculiar  weedy 
odor.  Especially  is  this  true  in  the  fall  or  late  summer.  If  such 
milk  is  heated  to  1600  to  1800  F.,  and  stirred  occasionally,  some  of 
these  taints  pass  off.  The  addition  of  a  small  amount  of  saltpeter 
will  improve  the  flavor  of  milk  where  such  foods  as  turnip  and 
sugar-beet  tops  are  fed.  This  remedy  is  often  applied  to  milk  in 
Canadian  cheese  factories,  during  the  fall  of  the  year  when  turnip 
tops  are  fed,  and  also  in  Germany  during  the  period  of  the  feeding 
of  sugar-beet  tops. 

Too  much  emphasis  cannot  be  placed  upon  the  food  that 
the  cows  receive.  While  it  is  true  that  much  of  the  desirable 
aroma  and  flavor  in  butter  is  due  to  bacterial  growth,  the  kind 
of  food  fed  to  cows  is  not  without  significance.  It  is  a  well-known 
fact  that  districts  such  as  Normandy  and  Denmark,  which  have 
become  famous  for  their  high  quality  of  dairy  products,  have  the 
best  of  pasture  and  winter  feeds. 

Besides  the  kind  of  food,  some  physiological  disturbances  of 
the  cow  may  cause  abnormal  taints  in  milk. 

(2)  Gases  or  taints  which  are  formed  in  the  milk  or  absorbed 
by  it  are  due  to  fermentation  and  absorption  respectively.  The 
former  cause  will  be  considered  in  a  separate  chapter,  and  the 
latter  cause  needs  little  explanation.  It  is  a  well-known  fact 
that  milk  and  most  of  its  products  have  the  special  property 
of  absorbing  odors  which  may  be  present  in  their  surroundings. 
For  this  reason,  milk,  as  well  as  other  dairy  products,  should  at 
all  times  be  kept  in  clean  utensils  and  pure  surroundings. 

Taints  appearing  in  milk  immediately  after  milking  are  due  to 
absorption  within  the  cow.  Taints  that  develop  on  standing  are 
due  to  bacterial  growth  in  the  milk,  or  to  absorption  from  impure 
surroundings.  In  the  prevention  and  removal  of  taints  from 
milk  the  first  step  is  to  remove  the  cause,  and  the  second  to 
eliminate  as  many  of  these  taints  as  possible  by  a  process  of 
aeration  or  pasteurization. 


22  BUTTER-MAKING  AND   COMPOSITION  OF  MILK 

Coloring-matter.— It  is  not  known  of  what  the  coloring- 
matter  in  milk  consists.  A  substance  named  lactochrome  has 
been  found  in  milk.  So  far  as  known,  this  coloring-substance  is 
closely  associated  with  the  fat  called  palmitin.  The  amount  of 
coloring-matter  varies  during  the  different  seasons  of  the  year. 
It  also  varies  according  to  the  different  breeds.  During  the 
spring  of  the  year,  when  cows  are  first  put  on  grass,  the  color  of 
of  the  butter-fat  is  always  higher  than  it  is  during  the  latter  por- 
tion of  the  summer.  During  the  winter,  the  fat  in  milk  is  quite 
pale.  By  feeding  the  cows  some  succulent  feed  in  the  winter, 
such  as  silage,  carrots,  and  beets,  the  color  of  the  butter-fat  is 
rendered  much  higher. 

From  this  it  would  seem  that  the  change  in  the  color  of  the 
fat  with  the  different  seasons,  and  with  the  food  given,  is  closely 
associated  with  chlorophyl,  the  coloring-matter  of  grass. 

Other  Constituents  of  Milk. — It  is  said  that  constituents 
such  as  citric  acid,  urea,  nuclein,  lecithin,  and  galactase  are 
present.  Babcock  maintains  that  he  has  discovered  a  sub- 
stance named  fibrin.  This  seems  to  be  similar  to  the  nuclein 
mentioned  by  Fleischmann,  if  not  the  same.  But  as  these 
substances  are  present  to  a  very  small  extent,  citric  acid,  urea, 
and  fibrin  being  present  to  the  extent  of  .12,  .007,  and  .0002 
per  cent  respectively  (Fleischmann  and  Babcock),  they  are  of 
little  importance. 


CHAPTER   II 
MILK  SECRETION 

The  Mammary  Gland  as  a  Secretory  Organ. — The  mammary 
gland  of  females  belonging  to  the  order  of  mammalia  secretes  a 
fluid  known  as  milk.  This  substance  is  strictly  a  secretory 
product.  There  are  two  kinds  of  glands  present  in  the  animal 
body,  viz.,  the  excretory  and  the  secretory.  Generally  speaking, 
an  excretory  gland  is  one  which  receives  or  absorbs  the  waste 
matter  of  the  body,  and  causes  it  to  be  carried  off  without  causing 
any  marked  change  to  take  place  in.  the  substance  excreted. 
A  secretory  gland  is  one  in  which  the  raw  material  is  obtained 
from  the  blood  and  then  manufactured  into  a  special  different 
product  within  the  gland  itself.  As  an  example  of  a  secretory 
gland,  the  milk-gland  of  the  cow's  udder  is  an  apt  illustration. 
The  glands  in  the  mouth  secreting  saliva,  and  those  in  the  walls  of 
the  stomach  secreting  the  digestive  fluids,  are  also  secretory 
glands. 

Internal  Structure  of  Cow's  Udder. — The  cow's  udder  is 
composed  of  two  separate  glands,  the  right  and  left  halves. 
These  two  glands  are  distinctly  separated  from  each  other  by  a 
fibrous  tissue  running  longitudinally.  This  fibrous  partition 
extends  along  the  abdomen  in  front,  and  back  to  a  point  between 
the  thighs  of  the  cow.  It  also  serves  to  hold  the  cow's  udder  in 
place.  There  is  no  connection  at  all  between  the  right  and  left 
glands,  and  consequently  milk  cannot  be  drawn  from  the  left 
side  over  to  the  right,  and  vice  versa. 

Each  of  these  right  and  left  halves  is  again  divided  into  two 
parts,  thus  making  the  cow's  udder  appear  to  be  divided  into 
quarters.  The  cow's  udder  may  then  be  said  to  consist  of  two 
glands,  one  on  each  side,  and  four  "  quarters,"  two  to  a  gland. 
The  division  between  the  two  quarters  of  a  gland  is  not  complete; 

23 


24 


MILK   SECRETION 


that  is,  there  is  enough  connection  between  the  two  to  allow 
a  portion  of  the  milk  to  be  drawn  from  the  rear  quarter  through 
the  front  teat  on  the  same  side,  and  vice  versa. 

The  milk-glands  proper  are  located  near  the  abdomen  and 
extend  a  trifle  downwards  into  the  udder.     The  remainder  of  the 


GLAND-LOBULE 


Fig.  2.  —Schematic  figure  showing  cross-section  of  cow's  udder;  and  also 
enlargement  of  epithelial  cells  in  alveoli  when  cow  is  giving  milk  (i).  Each 
alveolus  is  surrounded  with  a  membrane  called  tunica  propria.  Cell  nuclei 
not  shown.  When  cow  is  in  milk  they  are  also  enlarged.  When  not  the 
epithelial  cells  are  rial  and  the  nuclei  small  and  spindle  shaped  (2). 


udder  is  filled  with  ducts,  fibrous  and  connective  tissue,  muscle, 
nerves,  and  blood-vessels,  the  whole  udder  assuming  a  sort  of 
spongy  and  open  condition. 

The  teat  is  simply  a  cylindrical-shaped  body,  with  a  hollow 
tube  extending  down  through  the  center  of  it.     At  the  bottom 


INTERNAL   STRUCTURE   OF   COW'S   UDDER  25 

of  this  opening,  or  at  the  end  of  the  teat,  there  is  a  sphincter 
muscle,  which  in  some  cases  is  drawn  up  very  tight,  while  in 
other  instances  it  is  so  loose  that  it  will  not  prevent  the  milk  from 
escaping.  In  case  the  muscle  is  so  tight  that  the  milk  can  be 
drawn  only  with  difficulty,  it  may  be  relaxed  a  trifle  by  inserting 
a  small,  smooth  wooden  plug.  This  will  usually  dilate  the  open- 
ing sufficiently,  so  that  the  milk  may  be  drawn  with  comparative 
ease.  In  some  instances  this  muscle  is  so  tight  that  it  is  necessary 
to  relax  it  by  the  use  of  a  sharp  knife.  This,  however,  should  be 
done  with  surgical  skill;  otherwise  the  whole  muscle  is  likely  to  be 
so  injured  as  to  cause  the  milk  to  leak  away  at  all  times. 

The  upper  part  of  this  canal  in  the  teat  connects  with  what 
is  called  the  milk-reservoir.  The  size  of  this  reservoir  varies  in 
different  cows.  The  average  capacity  of  this  milk-cistern  is 
about  one  pint.  The  opening  from  this  reservoir  into  the  teat 
is  also  guarded  with  a  muscle.  Over  this  muscle  the  cow  has 
little  control;  over  the  muscle  at  the  lower  end  of  the  teat  she 
has  no  control  whatever. 

Opening  into  the  sides  and  top  of  this  reservoir  are  a  large 
number  of  tubes,  which  are  called  milk-ducts.  These  milk-ducts 
extend  from  the  reservoir  up  into  the  milk-gland.  They  radiate 
in  all  directions,  divide  and  subdivide,  so  as  to  form  a  very  large 
number  of  small  tubes.  These  milk-ducts  are  surrounded  with 
fibrous  muscular  tissue,  nerves,  and  blood-vessels.  They  are  all 
guarded  by  a  special  muscle  at  the  junction  with  the  main  milk- 
ducts,  from  which  they  radiate.  These  muscles  are  so  inti- 
mately connected  with  the  nerves  and  muscular  system  of  the 
cow  that  she  is  able  to  open  and  close  them  at  will.  There  are 
very  few  cows  that  are  not  able  to  hold  up  their  milk  during 
nervous  and  exciting  periods.  It  is  a  common  occurrence  for  a 
milker  to  get  only  a  small  part  of  the  milk  from  a  cow;  this  small 
amount  is  the  portion  which  is  present  in  the  teat  and  milk- 
reservoir.  Some  cows  are  able  to  hold  up  this  milk  also,  but  the 
majority  of  cows  cannot  perfectly  control  the  muscle  which 
guards  the  entrance  to  the  teat.  The  milk  which  is  present  in 
the  milk-ducts  and  which  has  to  pass  through  these  junctions 
referred  to  above  can  be  held  up  by  most  cows  at  will. 


26  MILK  SECRETION 

All  of  the  small  milk-ducts  end  in  small  sac-like  bodies,  each 
of  which  is  called  a  gland-lobule  or  ultimate  follicle.  The  gland- 
lobules  enclose  numerous  individual  microscopical  bodies  called 
alveoli  or  acini;  these  are  the  organs  which  possess  the  proper 
secretory  functions.  Their  outer  covering  is  a  membrane  called 
the  tunica  propria;  within  this  there  is  an  intermediate  layer  of 
cell-tissue,  and  an  inside  layer  composed  of  cells,  which  are  named 
the  epithelial  cells.  These  epithelial  cells  within  the  alveoli  are 
supplied  with  blood  from  the  cow's  system.  During  lactation 
they  assume  a  different  form,  swelling  and  extending  into  the 
cavity  of  the  alveoli  when  the  cow  is  yielding  milk  abundantly, 
and  when  she  is  not  in  milk  the  alveoli  are  flat.  A  certain 
number  of  alveoli  are  tributary  to  one  particular  duct  leading 
from  the  gland-lobule  into  still  larger  milk-ducts. 

Each  aggregation  of  gland-lobules,  tributary  to  one  milk- 
cistern,  constitutes  a  lobe,  and  may  be  likened  to  a  side  branch 
of  a  bunch  of  grapes.  Each  separate  grape  may  represent  a 
gland-lobule.  The  seeds  within  the  grape,  if  we  imagine  each 
seed  to  be  hollowed  out  and  lined  with  small  column-like  bodies, 
may  be  likened  to  the  alveoli.  These  column-like  bodies  would 
then  represent  the  epithelial  cells.  The  stem  leading  from  each 
individual  grape  may  represent  the  small  duct  which  carries  the 
milk  on  to  the  larger  ducts.  The  main  stems  of  the  bunch  may 
represent  the  larger  ducts  that  enter  into  the  milk-reservoir.  The 
air  which  everywhere  fills  the  openings  or  interstices  of  the  various 
parts  of  the  bunch  of  grapes  may  be  likened  to  the  fibrous  fatty 
tissue  between  the  alveoli  and  the  lobules  of  the  gland. 

Theories  of  Milk  Secretion. — Although  the  theories  of  milk 
secretion  have  been  studied  considerably,  many  things  in  this 
connection  are  not  well  understood.  Previous  to  the  year 
1840  it  was  thought  that  the  only  function  of  the  milk-gland 
was  to  filter  the  milk  as  it  transuded  from  the  blood.  It  was 
supposed  that  the  quality  and  quantity  of  milk  depended  entirely 
upon  the  food.  The  theory  has  also  been  advanced  that  the 
major  portion  of  the  milk  constituents  is  a  decomposition  of 
the  product  of  the  lymph  bodies  of  the  blood.  It  was  believed 
that  the  lymph  bodies  were  a  source  of  nourishment  to  the  fetus. 


THEORIES  OF  MILK   SECRETION  27 

and  that  the  calf  received  its  nourishment  from  the  same  source 
after  it  was  born  as  it  did  previous  to  birth.  It  was  supposed  that 
after  the  birth  of  the  calf  the  opening  on  the  uterus  through  which 
the  food  was  supplied  was  closed,  and  that  a  new  opening  was 
formed  in  the  milk-gland.  These  two  theories  have  now  been 
practically  overthrown.  It  has  been  demonstrated  that  the 
major  portion  of  the  milk  is  formed  within  the  milk-gland.  The 
fat,  casein,  milk-sugar,  and  part  of  the  albumen  are  supposed  to 
be  formed  in  the  udder.  This  conclusion  is  substantiated  by  the 
fact  that  these  substances  do  not  appear  in  the  blood,  at  least  not 
to  such  an  extent  as  to  warrant  the  assumption  that  they  are  not 
manufactured  in  the  cow's  udder.  The  total  amount  of  fat  in 
the  blood  of  the  cow  would  not  equal  the  fat  in  the  milk  from  one 
milking. 

By  some  it  is  maintained  that  the  substances  in  milk  which 
are  found  in  solution  may  be  transuded  directly  from  the  blood. 
Here  again  milk-sugar  is  found  to  be  in  perfect  solution  in  the 
milk.  But  this  substance  can  be  found  nowhere  in  nature 
besides  in  milk.  It  is  not  present  in  the  blood  of  the  animal; 
consequently  it  must  be  manufactured  within  the  gland  itself. 
The  water  of  milk,  and  the  ash  constituents  which  are  in  solu- 
tion, are  probably  transuded  directly  from  the  blood.  No 
attempts  have  been  made  to  determine  definitely  how  casein  and 
albumen  are  formed  within  the  gland. 

According  to  the  theory  which  has  been  advanced,  the  fat  is 
formed  by  the  breaking  down  of  the  epithelial  cells.  When  the 
breaking-down  process  is  completed,  the  transformed  cells  appear 
at  the  opening  of  the  alveoli  in  the  form  of  distinct  fat-globules. 
This  is  supposed  to  be  the  origin  and  formation  of  fat-globules 
in  milk;  so  it  may  be  said  that  so  far  as  known  the  fat  is  the 
result  of  a  breaking  down  of  degenerated  epithelial  cells. 

Dr.  Bitting  asserts  that  the  formation  of  milk  solids  in  the 
cow's  udder  is  probably  due  to  a  metabolic  process  rather  than 
to  a  degenerative.  Collier  found  that  a  cow  giving  a  normal 
amount  of  milk  would  secrete  about  136,000,000  fat-globules 
per  second.  He  also  suggests  that  a  cow  secretes  about  5  pounds 
of  milk  solids  per  day.     As  a  cow's  udder  weighs  only  about  2 J 


28  MILK   SECRETION 

pounds,  the  whole  udder  would  have  to  be  renewed  twice  daily. 
This  is  not  consistent  with  our  presi  nt  knowledge  of  tissue 
building. 

The  chief  incentive  to  milk  secretion  is  maternity.  As  soon 
as  the  young  mammal  is  born  the  blood  which  went  to  the 
uterus  to  supply  the  calf  is  turned  toward  the  udder  instead. 


Fig.  3. — A  schematic  figure  showing  the  course  of  the  artery  leading  to  the 
mammary  gland  and  the  veins  returning  to  the  heart.  The  light-colored 
lines  represent  arteries  and  the  dark-colored  lines  the  veins.  (From  Bitting, 
Twelfth  An.  Report,  Indiana.) 

As  soon  as  this  current  of  blood  begins  to  flow,  all  of  the  blood- 
vessels and  capillaries  in  the  cow's  udder  swell.  This  causes  the 
minute  blood-vessels  or  capillaries  which  form  a  network  in  the 
walls  of  the  alveoli  to  swell,  and  their  swelling  stimulates  the 
epithelial  cells  to  activity. 

Conditions  Affecting  Secretion  of  Milk. — There  are  a  great 
many  conditions  which  affect  the  milking  capacity  of  a  cow. 
These  conditions  may  be  conveniently  grouped  into  two  classes 


CONDITIONS   AFFECTING   SECRETION   OF   MILK  29 

according  to  their  causes:    (i)  conditions  which  are  controlled 
largely  by  man,  and  (2)  conditions  which  are  inherent  in  the  cow. 

1.  Some  of  the  chief  conditions  which  reduce  the  secretion  of 
milk  and  are  largely  controlled  by  man  are:  improper  care 
and  treatment  of  the  cow,  lack  of  proper  food,  incomplete  and 
and  improper  milking,  irregularity,  and  long  periods  between 
milkings.  Pregnancy,  nervousness,  or  excitement  of  any  kind 
affects  the  proper  working  of  the  milk-glands  considerably. 
These  latter  causes,  however,  are  not  always  controlled  by  man. 

2.  Without  denying  the  influence  of  those  conditions  men- 
tioned above,  the  conditions  which  chiefly  affect  the  milk- 
secreting  capacity  are  inherent.  It  does  not  matter  how  much 
good  care  and  food  a  cow  receives,  if  she  does  not  possess  these 
inherent  necessary  qualities.  As  was  mentioned  before,  the 
milk-secreting  capacity  depends  upon  the  number  of  gland- 
lobules,  the  amount  of  blood  which  is  supplied  to  these  secretory 
parts,  and  the  capacity  of  the  cow  to  digest  and  assimilate  food, 
and  possibly  upon  a  stimulating  body  fluid  not  yet  well  under- 
stood. 

The  number  of  gland-lobules  is  believed  to  increase  until  the 
cow  is  about  seven  years  old.  The  milk-secreting  glands  are 
present  only  in  a  rudimentary  form,  until  the  cow  has  had 
her  first  calf,  or  is  well  advanced  in  the  first  stage  of  pregnancy. 
The  gland-lobules  then  increase  in  number  up  to  the  age  of  about 
seven.  The  relative  number  of  lobules  in  the  cow's  udder  can 
only  be  approximately  ascertained.  The  size  of  the  udder  in 
some  measure  indicates  this.  A  cow  with  a  large  flexible  udder'is 
usually  a  good  milker,  due  to  the  fact  that  a  large  udder  usually 
contains  a  large  number  of  gland-lobules. 

The  amount  of  blood  which  is  turned  through  the  cow's  udder 
to  supply  the  milk-secreting  cells  may  be  approximately  ascer- 
tained by  the  size  of  the  blood  vessels.  The  blood  from  the  heart 
enters  the  udder  near  the  region  of  the  hips.  It  then  passes  down 
through  the  udder,  along  the  abdomen  just  beneath  the  skin, 
until  it  reaches  a  point  about  midway  between  the  flank  and  the 
girth.  At  this  place  it  penetrates  the  abdominal  wall  and  enters 
the  thorax.     The  place  at  which  the  blood  penetrates  the  abdom- 


30  MILK  SECRETION 

inal  wall  may  be  felt  with  the  finger.  It  is  supposed  that  the 
size  of.  this  hole  is  in  some  measure  indicative  of  the  milk-produc- 
ing capacity  of  the  cow.  This  opening  in  the  abdominal  wall  is 
called  the  milk-hole  or  milk-fountain.  Large  irregular  veins  are 
considered  a  much  better  indication  of  good  milking  properties 
than  small  straight  veins. 

The  formation  of  gland-lobules  is  entirely  inherent  in  the  cow. 
The  only  way  that  these  may  be  increased  is  through  selection 
and  breeding.  The  amount  of  blood  which  passes  through  the 
cow's  udder  is  also  largely  inherent,  although  this  may  in  a  small 
measure  be  affected  by  the  amount  and  quality  of  food  given  to 
the  cow.  It  should  at  all  times  be  remembered  that  a  cow  is  not 
a  mere  receptacle  into  which  so  much  food  can  be  introduced,  and 
from  which  so  much  milk  can  be  drawn.  After  giving  due  credit 
for  the  influence  of  all  other  conditions,  we  must  still  recognize 
that  the  inherent  conditions  affecting  the  secretion  of  milk  are 
the  most  important. 

External  Appearance  of  the  Udder. — A  cow's  udder  should  be 
well  and  symmetrically  formed.  It  should  be  square  and  wide, 
and  extend  well  along  the  abdomen  of  the  cow,  and  back  up 
between  the  thighs.  When  the  udder  is  empty  it  should  be  soft 
and  flexible.  The  teats  should  be  medium  large,  be  placed  well 
apart,  and  point  downwards. 

There  should  be  little  or  no  depression  in  the  udder  between 
the  teats;  that  is,  each  quarter  should  not  appear  distinct  and 
separate  when  viewed  from  the  exterior. 

The  cow's  udder  should  be  covered  with  fine,  soft,  downy 
hair.  A  light  golden  yellow  is  said  to  be  indicative  of  a  good 
quality  of  milk. 

A  firm,  fleshy  udder  is  undesirable.  In  the  first  place,  it  is 
not  indicative  of  good  milking  qualities,  and,  secondly,  such 
an  udder  is  predisposed  to  inflammatory  diseases. 

Milk-fever. — This  is  a  common  disease  in  fresh  cows.  It  is 
due  to  a  congested  condition  of  the  cow's  udder.  The  decompo- 
sition products  of  the  colostrum  milk  in  the  udder  are  absorbed  by 
the  blood,  and  produce  the  characteristic  symptoms  of  milk-fever. 
Dr.  Peters,  of  the  Nebraska  Experiment  Station,  says  that  a  good 


MILK-FEVER  31 

and  simple  remedy  for  a  diseased  udder  is  to  pump  it  full  of  air. 
This  can  be  accomplished  with  an  ordinary  bicycle  pump.  After 
some  air  has  been  pumped  in,  the  cow's  udder  should  be  worked  or 
massaged  with  the  hand  so  as  to  cause  the  air  to  pass  through 
the  quarter.  He  claims  that  the  udder  can  thus  be  restored  to  its 
normal  condition  very  quickly,  thereby  preventing  and  even 
curing  milk-fever.  In  case  the  udder  is  caked  very  badly,  apply  a 
hot  poultice.  Small  five-  or  ten-pound  bags  filled  with  bran 
and  kept  hot  will  prove  very  satisfactory.  A  compress  consisting 
simply  of  a  piece  of  heavy  cloth  is  also  used.  It  should  be  put 
on  so  that  it  lifts  up  the  entire  udder,  and  tied  over  the  back  of 
the  cow.  Straw  should  be  put  underneath  it  on  the  back  so  that 
the  cord  will  not  injure  the  animal. 


CHAPTER   III 
PROPERTIES  CF  MILK 

Color. — The  coloring  matter  of  milk  is  associated  with  the  fat. 
According  to  extensive  investigations,  made  by  Eckles  and 
Palmer  at  the  Missouri  Station,  this  color  is  due  to  carotin,  so 
called  because  it  is  the  coloring  matter  of  the  carrot.  It  is  found 
in  green  plants  and  is  closely  associated  with  the  chlorophyl, 
which  hides  its  presence.  It  is  not  manufactured  by  the  animal. 
Animals  which  produce  milk  rich  in  fat,  in  the  form  of  large  fat- 
globules,  possess  the  ability  to  utilize  this  coloring  matter  to  a 
greater  degree  than  do  animals  which  produce  milk  having  a  lower 
fat  content  and  smaller  fat-globules.  This  explains  the  downward 
gradation  of  the  color  of  the  fat  in  the  milk  as  we  pass  from  the 
Guernsey  and  Jersey  to  the  Shorthorn,  Ayrshire  and  Hols te in 
breeds. 

Flavor. — Milk  has  a  sweet  flavor,  and  a  faint  odor.  Fresh 
milk  has  a  peculiar  taste  and  odor,  which  pass  off  when  it  is 
exposed  to  the  air.  The  flavor  is  affected  by  foods  and  con- 
ditions of  the  cow,  as  mentioned  under  "  Abnormal  Milk." 

Opacity  of  Milk. — Milk  is  opaque,  except  when  seen  in  very 
thin  layers;  then  it  is  slightly  transparent.  The  opacity  of  milk 
is  due  to  the  presence  of  the  fat  and  nitrogenous  matter.  When 
these  substances  are  filtered  away  on  a  fine  clay  filter  (the  Cham- 
berland),  the  filtrate  which  passes  through  is  clear  and  trans- 
parent. It  has  been  maintained  that  the  fat  in  milk  is  the  chief 
cause  of  its  opacity,  and  that  the  percentage  of  fat  could  be 
determined  according  to  the  degree  of  opacity  and  transparency 
of  milk  with  an  instrument  named  pioscope ;  but  it  was  soon  found 
out  that  the  size  of  the  fat-globules,  as  well  as  the  number,  had 
considerable  influence  upon  the  degree  of  opacity  of  milk.  For 
that  reason,  this  method  of  determining  the  amount  of  fat  in 

32 


CHEMICAL   REACTION  OF   MILK  33 

milk  was  not  reliable.  The  fat-globules  themselves  are  said  to  be 
almost  transparent,  yet  the  color  and  opacity  of  milk  is  largely 
due  to  their  presence.  This  characteristic  may  perhaps  be 
explained  by  assuming  that  the  fat-globules  in  milk  deflect  the 
light  instead  of  allowing  it  to  pass  through  them. 

After  the  fat  has  been  removed,  the  milk  still  continues  to 
be  opaque.  When  the  albuminoid  matter  has  been  removed 
and  filtered  off  the  filtrate  becomes  clear  and  transparent. 

Chemical  Reaction  of  Milk. — Milk  when  fresh  shows  an 
amphoteric  reaction,  which  means  that  it  exhibits  both  an  alkaline 
and  an  acid  reaction  when  tested  with  litmus  paper.  It  turns 
blue  litmus  paper  red,  and  red  litmus  paper  blue.  This  peculiar 
behavior  of  milk  is  said  to  be  due  to  the  caseous  matter  in  the 
milk,  which  itself  has  an  acid  reaction,  while  the  remainder  of 
the  serum  has  a  slight  alkaline  reaction.  By  testing  the  reaction 
of  fresh  milk  with  a  tenth  normal  alkali  solution,  and  using 
phenolphthalein  as  an  indicator,  an  acid  reaction  is  obtained. 
After  standing,  milk  soon  becomes  distinctly  acid,  due  to  a 
change  of  the  milk-sugar  into  acids,  chiefly  lactic  acid,  through 
the  action  of  micro-organisms.  Richmond  maintains  that  the 
amphoteric  reaction  of  milk  has  acquired  a  false  importance,  as  he 
believes  that  the  neutrality,  as  measured  by  the  action  of  litmus 
paper,  is  not  chemical  neutrality. 

Specific  Gravity  of  Milk. — By  specific  gravity  of  milk  we 
mean  the  weight  of  the  milk  as  compared  to  that  of  an  equal 
volume  of  water  at  the  same  temperature.  If  a  certain  volume 
of  water  weighs  iooo  pounds,  an  equal  volume  of  milk  at  the 
same  temperature  and  under  the  same  conditions  will  weigh 
about  1032  pounds.  Reducing  the  figure  to  a  basis  of  1,  as  is 
always  done,  the  comparison  between  the  two  equal  volumes  of 
water  and  milk  will  be  1  and  1.032.  This  latter  figure  represents 
the  average  specific  gravity  of  normal  milk. 

It  can  be  readily  seen  that  the  correct  specific  gravity  can 
be  obtained  only  at  one  given  temperature,  for,  as  the  tempera- 
ture of  the  substance  becomes  higher,  the  density  of  it  grows  less, 
and  consequently  the  specific  gravity  will  be  less.  The  tempera- 
ture at  which  the  lactometers  are  standardized  is  60  °  F. 


34  PROPERTIES  OF  MILK 

The  specific  gravity  of  milk  will  also  vary  according  to  the 
relative  variation  in  amounts  of  the  different  components.  If  a 
sample  of  milk  is  rich  in  solids  not  fat,  as,  for  instance,  skimmed 
milk,  the  specific  gravity  will  be  high  and  usually  between  1.033 
and  1.037.  K  the  sample  of  milk  is  rich  in  fat,  as,  for  instance,  in 
cream,  the  specific  gravity  will  be  less. 

The  specific  gravity  of  milk  is  lessened  by  the  addition  of 
water.  Owing  to  this  fact  it  was  first  thought  that  adulteration 
of  milk  with  water  could  be  detected  by  testing  its  specific  grav- 
ity. But  this  method  was  soon  found  to  be  erroneous,  as  it  is 
possible  to  take  cream  away  and  add  water  in  such  a  proportion 
as  not  to  alter  the  specific  gravity  of  the  sample.  A  low  specific 
gravity  may,  however,  cause  the  suspicion  that  the  milk  has 
been  adulterated,  and  the  test  for  water  adulteration  can  be 
supplemented  by  testing  it  for  fat. 

As  has  been  mentioned  before,  the  lactometer  reading  should 
be  taken  at  6o°  F.  If  the  temperature  of  the  milk  is  above  or 
below,  corrections  must  be  made.  The  amount  of  correction 
which  will  give  approximate  results  is  .1  of  a  degree  added  to  the 
lactometer  reading  for  every  degree  Fahrenheit  of  tempera- 
ture above  6o°  F.,  and  .1  of  a  degree  subtracted  from  the  lactom- 
eter reading  for  every  degree  of  temperature  below  6o°  F.  The 
temperature  of  milk  when  tested  for  lactometer  reading  should 
never  go  any  lower  than  io°  below  6o°,  nor  any  higher  than  io° 
above  6o°.  This  would  leave  the  range  of  temperature  between 
500  and  700  F. 

In  chemical  laboratories,  the  specific  gravity  of  milk  is  usually 
determined  by  the  use  of  a  picnometer. 

In  practice  there  are  three  instruments  in  general  use  for 
determination  of  lactometer  reading,  or  specific  gravity,  viz., 
Quevenne  lactometer,  New  York  Board  of  Health  lactometer 
and  the  ordinary  hydrometer.  The  Quevenne  lactometer  is  the 
one  that  is  used  chiefly  in  creameries.  The  graduation  of  each 
one  of  them  is  given  in  the  accompanying  diagram.  It  may  be 
seen  from  the  figures  that  in  order  to  change  the  Quevenne 
lactometer  reading  into  specific  gravity,  all  that  is  necessary  is 
to  add  1000  and  divide  the  sum  by  1000.     In  changing  the 


NATURAL   SEPARATION  OF  CREAM  AND  MILK 


35 


1.005 


1.010 


1.015 


specific  gravity  into  lactometer  reading  the  reverse  process  will 
give  correct  results. 

The  hydrometer  gives  the  specific  gravity  directly.  The 
Board  of  Health  lactometer  has  a  special  graduation.  When 
this  lactometer  was  devised  it  was  thought  that  1.029  was  the 
minimum  specific  gravity  of  un- 
adulterated milk.  The  scale  on  this  1.000 
lactometer  was  made  from  zero 
to  1 20,  zero  marking  the  point  which 
represents  the  specific  gravity  of 
water,  namely,  1,  while  100  is  the 
point  which  is  assumed  to  represent 
the  least  specific  gravity  of  milk, 
1.029.  If  the  specific  gravity  of  a 
certain  sample  of  milk  fell  to  90,  it 
indicated  that  there  was  10  per  cent 
of  water  present.  If  it  fell  to  80, 
it  indicated  that  there  was  20  per 
cent  of  water,  etc. 

In  order  to  calculate  the  total 
solids,  and  solids  not  fat,  of  milk, 
it  is  necessary  to  know  its  lactometer 
reading,  and  the  percentage  of  fat 
in  it.  Knowing  these  factors,  by 
the  use  of  the  following  formula 
given  by  Farrington  and  Woll,  and    «s»  specific  Gravity  Scale. 

deduced    from    Fleischmann's    work,    "N"  New  York  State. 

"Q '  Quevenne. 
the  total  solids,  and  solids  not    fat,     FlG  4._Comparative  gradua. 

can  be  found.  tion  of  lactometer  stems. 


1.030 


1.035 


Solids  not  fat  =  J  lact.  reading +.2  times  the  fat. 
Total  solids     =  fat + solids  not  fat. 


Natural  Separation  of  Milk  and  Cream. — When  milk  is 
allowed  to  stand  quietly  for  a  short  time,  a  layer  having  a  rich- 
yellow  color  comes  to  the  surface.  This  is  the  cream,  and  con- 
tains most  of  the  fat.     This  separation  is  due  chiefly  to  the 


36 


PROPERTIES  OF  MILK 


difference  in  weight,  or  specific  gravity,  of  the  fat-globules  and 
the  serum.  The  force  which  acts  upon  the  globule  of  fat  is  the 
difference  in  weight  between  the  fat-globule  and  the  serum  which 
it  displaces,  minus  the  resistance  with  which  it  meets  in  its  upward 
passage.  This  force  is  great  in  milk  with  a  high  degree  of  vis- 
cosity and  slighter  in  milk  of  a  limp  and  liquid  consistency. 
While  the  addition  of  water  to  milk  reduces  its  viscosity  it  also 
lowers  its  specific  gravity.     Hence,  the  so-called  "  dilution  cream 


FlG    5  _ Standardized  milk.     Showing  the  amount  of  cream   on   milk   containing 
the  designated  per  cent  of  butter-fat.     (From  Bui.  92,  111.) 

separator "  has,  generally  speaking,  little  to  recommend  it. 
While  the  skim-milk  may  give  a  lower  test  we  must  remember 
that  there  is  a  greater  quantity  of  it.  Furthermore,  it  lacks  the 
palatability  and  feeding  value  of  undiluted  skim-milk.  But  this 
is  a  point  that  need  not  be  labored,  since  the  hand  separator  has 
all  but  superseded  the  different  methods  of  setting  milk. 

In  normal  milk,  the  amount  of  fat  left  in  the  skimmed  milk  by 
natural  creaming  is  about  4  per  cent.  The  fat  which  is  left  in 
this  skimmed  milk  is  largely  composed  of  very  small  globules. 
This  is  due  to  the  fact  that  the  resistant  force  on  these  small 
globules  is  equal  to  or  greater  than  the  buoyant  force  acting  upon 
them. 


ADHESION  OF  MILK  37 

The  completeness  of  natural  skimming  is  to  a  certain  extent 
based  upon  the  mathematical  law  which  is  stated  as  follows: 
"  The  surfaces  of  two  spheres  are  to  each  other  as  the  squares  of 
their  diameters,  and  their  cubical  contents  are  to  each  other 
as  the  cubes  of  their  diameters."  The  larger  the  globules  are, 
the  greater  the  surface  is,  and  the  greater  the  resisting  force  to 
which  they  are  subjected.  From  the  law  stated  it  can  be  seen 
that  as  the  size  of  the  globule  increases,  the  cubical  content 
increases  more  rapidly  than  the  surface.  If  a  fat-globule  were 
split  up  into  smaller  ones,  there  would  be  more  surface  exposed 
to  the  serum  than  was  the  case  while  the  fat  was  present  in  one 
globule. 

For  illustration,  suppose  two  globules  of  fat  to  have  diameters 
of  4  and  2  inches  respectively.  The  squares  would  be  16  inches 
and  4  inches  respectively;  their  cubes  would  be  64  inches  and  8 
inches  respectively.  It  will  thus  be  seen,  according  to  the 
law  quoted  above,  that  the  larger  globule  has  a  surface  only  four 
times  as  great  as  that  of  the  smaller  one ;  but  the  cubical  content 
of  the  larger  globule  is  eight  times  that  of  the  smaller  one.  This 
illustrates  why  the  large  globules  rise  in  cream  more  quickly  than 
the  small  ones.  In  this  particular  instance  the  upward  force  the 
larger  globule  is  subjected  to  is  eight  times  greater  than  that  of 
the  smaller  one,  while  the  resistant  force  is  only  four  times  as 
great  as  that  of  the  small  one. 

Adhesion  of  Milk. — Normal  sweet  milk  adheres  to  wood, 
glass,  and  metals  to  a  greater  extent  than  does  water.  Whole 
milk  has  greater  adhesive  properties  than  skimmed  milk.  A 
paper  moistened  with  milk  or  cream  makes  a  label  that  will  stick 
to  any  dry  object;  the  same  paper  moistened  with  skimmed 
milk  has  less  adhesive  power.  The  adhesive  properties  of  milk 
are  also  due  to  the  condition  of  the  nitrogenous  matter.  This 
fact  is  made  use  of  in  painting  and  whitewashing.  Slaked  lime, 
when  mixed  with  buttermilk,  or  milk  of  any  kind,  gives  a  white- 
wash which  will  remain  on  objects  much  longer  than  that  made 
by  mixing  with  water. 

Viscosity  of  Milk. — Milk  is  more  viscous  than  water.  The 
degree  of  viscosity  of  fresh  milk  varies  chiefly  with  the  tempera- 


38  PROPERTIES   OF  MILK 

lure  and  fat  content.  So  far  as  understood,  the  lower  the  tem- 
perature, the  greater  the  viscosity.  Development  of  acid,  and 
high  temperature  lessen  the  viscosity  of  milk.  Pasteurized  milk 
or  cream  is  less  viscous  than  the  same  milk  or  cream  unpasteur- 
ized. This  lack  of  body  can  again  be  restored  by  adding  a  little 
viscogen,  as  recommended  by  Babcock  and  Russell.  It  is  not 
advisable  to  use  it,  however,  as  it  does  not  add  materially  to  the 
nutritive  value  of  milk,  but  merely  restores  the  body. 

The  great  viscosity  of  thick  cold  cream  makes  it  difficult  to 
churn,  as  most  butter-makers  have  discovered.  It  adheres 
to  the  inside  of  the  churn  and  simply  rotates  instead  of  being 
agitated.  Cream  that  is  cold  and  thick  whips  more  easily  than 
thin,  warm  cream,  as  the  viscosity  is  so  great  that  the  .air  incor- 
porated cannot  escape  so  easily.  In  ice-cream  making,  for  the 
same  reason,  a  greater  yield  is  obtained  by  using  cold,  thick  cream. 

Specific  Heat  of  Milk. — The  specific  heat  of  milk  is  less  than 
that  of  water;  that  is,  it  requires  less  heat  to  warm  a  definite 
amount  of  milk  to  a  certain  temperature  than  it  does  to  heat  the 
same  quantity  of  water  to  the  same  temperature.  It  also  takes 
less  ice  to  cool  the  same  volume  of  milk  to  a  certain  temperature 
than  it  does  to  cool  the  same  quantity  of  water  to  the  same  tem- 
perature. The  specific  heat  of  milk  is,  according  to  Fjord,  .94. 
The  specific  heat  of  cream  is  about  .7.  It  varies  according  to  the 
percentage  of  fat  in  the  cream.  The  specific  heat  of  butter  is 
about  .4.  From  these  figures  it  will  be  seen  that  it  takes  less 
heat  to  warm  milk,  cream,  and  butter,  and  less  cold  to  cool  the 
same  substances,  than  it  does  to  heat  and  cool  water;  but  it  takes 
a  longer  time  to  heat  or  to  cool  milk,  cream,  and  butter;  that  is, 
the  milk,  cream,  and  butter  are  not  as  rapid  conductors  of  heat 
and  cold  as  is  water. 

The  maximum  density  of  milk  is  not  reached,  like  that  of 
water,  at  40  C.  but  at  about  .3°  C.  The  boiling-point  of  milk  is  a 
trifle  higher  and  the  freezing-point  a  trifle  lower  than  that  of 
water. 

Effect  of  High  Heating  (1800  and  above)  on  Properties  of 
Milk. — The  chiel  effects  of  heat  upon  milk  may  be  summarized 
in  the  following  headings: 


EFFECT  OF  HIGH  HEATING  ON  PROPERTIES  OF  MILK      39 

(i)  It  destroys  nearly  all  germs  present  in  the  milk. 

(2)  It  diminishes  the  viscosity,  or  body. 

(3)  It  drives  off  gases. 

(4)  It  imparts  a  cooked  taste  (especially  if  not  heated  and 
cooled  properly.) 

(5)  It  precipitates  some  of  the  albuminoids  and  ash  constit- 
uents. 

(6)  It  destroys  the  properties  of  enzymes  present  in 
milk. 

(7)  It  divides  or  splits  up  the  clusters  and  fat-globules. 

(8)  It  caramelizes  some  of  the  sugar. 

1.  Destroys  Nearly  all  Germs. — Heating  milk  to  a  tempera- 
ture of  about  1800  F.  for  ten  minutes  destroys  most  of  the  germs 
present.  This  is  the  temperature  used  in  most  creameries  for 
pasteurization.  The  details  concerning  the  different  effects  of 
temperature  upon  growth  of  germs  properly  comes  under  the 
heading  of  bacteriology,  and  will  be  referred  to  more  in  detail  in 
the  chapter  on  "  Ferments  in  Milk." 

2.  Diminishes  the  Visc:sity,  or  Body. — Heating  milk  or 
cream  diminishes  its  viscosity;  that  is,  it  lessens  the  body  or  con- 
sistency; and  in  cities  where  milk  or  cream  is  sold  directly  to 
consumers,  heated  milk  appears  as  if  it  had  been  adulterated. 
This  diminution  in  the  body  is  claimed  to  be  due  to  a  breaking 
up  of  the  clusters,  and  the  fat-globules  and  the  caseous  matter. 
The  chemical  union  of  some  of  the  calcium  salts  and  the  casein 
is  altered  or  destroyed. 

The  consistency  of  milk  or  cream  can  be  restored  by  adding 
a  substance  named  viscogen.  Russell  and  Babcock  *  advise  this 
method  of  overcoming  the  apparent  defect  caused  by  heating. 
It  consists  of  making  a  strong  solution  of  cane-sugar  and  mixing 
it  with  freshly  slaked  lime.  This  mixture  is  allowed  to  stand, 
and  the  clear  solution  coming  to  the  top  is  the  viscogen,  which, 
when  drawn  off  and  used  in  the  proportion  of  one  part  of  viscogen 
to  from  100  to  150  parts  of  cream,  restores  its  body.  This  is 
due  to  the  fact  that  viscogen  causes  the  fat-globules  to  cluster 
together  again,  and  the  lime  in  the  viscogen  may  combine  with  the 

1  Bulletin  No.  54,  Wisconsin,  1896. 


40  PROPERTIES   OF   MILK 

nitrogenous  constituents  in  such  a  way  as  to  aid  in  the  restora- 
tion of  the  body  of  the  cream  or  milk. 

Nearly  all  dairy  laws  forbid  the  addition  of  any  foreign  sub- 
stances to  milk  or  cream.  If  viscogen  is  added,  Babcock  and 
Russell  suggest  tha.  it  be  named  visco-milk,  visco-cream,  etc. 
When  the  modification  is  made,  no  objection  can  be  raised  to  its 
legitimate  use. 

3.  Drives  off  Gases. — When  milk  is  heated,  taints  and  gases  of 
different  kinds  pass  off  to  some  extent.     This  is  facilitated  by 


-  »  ** uvaser* 

.,'    .      -* 

3  '  ! 

Zm 

\  ^    :M 

_  ^^     _  •  k V.' 

Fig.  6. — Microscopic  appearance  of  milk,  showing  natural  grouping  of  the  fat- 
globules.     Single  group  in  circle,  highly  magnified.     (From  Bui.  64,  Wis.) 

heating  and  stirring  in  an  open  vessel.  Many  of  these  gases 
also  escape  when  milk  is  aerated  and  cooled  in  a  pure  atmos- 
phere. 

4.  Imparts  a  Cooked  Taste. — When  milk  is  heated  to  1600  F. 
or  above,  it  assumes  a  distinctly  cooked  taste,  which  makes  it 
disagreeable  as  a  food  for  many  people.  On  this  account,  milk 
for  city  supply  in  America  is  not  generally  heated  above  145 °  F. 
In  practically  all  cities  where  milk  is  consumed  directly,  it  is 
subjected  to  low  temperature  pasteurization  (1450  F.)  and  held 
at  this  temperature  for  twenty  to  thirty  minutes.  Under  this 
system  the  disadvantages  of  high  pasteurization  are  overcome. 

For  butter-making  purposes  there  are  no  objections  to  pas- 
teurizing cream  at  a  high  temperature.     The  common  practice 


EFFECT  OF  HIGH  HEATING  ON  PROPERTIES  OF  MILK   41 

in  most  of  our  up-to-date  creameries  to-day  is  to  pasteurize 
the  cream,  under  the  vat  or  holding  system,  to  1700  F.  or  above, 
or,  under  the  flash  system,  to  at  least  1800  F. 

The  reason  why  this  cooked  flavor  is  found  in  milk  when 
heated  is  not  well  understood.  It  is  supposed  to  be  due  to 
the  effect  which  heat  has  upon  the  nitrogeneous  constituents 
and  the  sugar. 

5.  Precipitates  Albuminoid  and  Ash  Constituents. — When 
milk  is  heated,  there  is  a  tendency  for  the  soluble  salts  and  a 
portion  of  the  albuminoids  to  be  thrown  down,  or  changed  into 
an  insoluble  form. 

The  higher  the  milk  is  heated,  the  greater  is  this  tendency. 
If  a  sample  of  milk  in  a  flask  is  subjected  to  intense  heat,  and 
then  allowed  to  stand,  a  fine  white  sediment  will  be  deposited  on 
the  bottom.  This  is  believed  to  consist  of  minerals  precipitated 
from  the  milk. 

When  milk  has  been  heated  to  about  1700  F.,  and  cooled, 
rennet  is  unable  to  precipitate  the  curd  in  a  normal  way.  The 
curd  resulting  from  adding  rennet  to  pasteurized  milk  is  flocculent 
in  nature.  It  does  not  assume  that  smooth  and  even  texture 
that  curd  from  raw  milk  has  when  precipitated  with  rennet. 
The  behavior  of  pasteurized  milk  towards  rennet  can  be  ren- 
dered normal  by  adding  a  small  quantity  of  calcium  chloride 
(CaCl).  Whether  this  would  affect  the  quality  of  cheese  mate- 
rially has  not  yet  been  determined  definitely.  According  to  G. 
Fascetti,1  if  pasteurized  milk  is  used  for  cheese-making,  the 
cheese  ripens  more  slowly  than  when  made  from  raw  milk.  The 
same  investigator  also  claims  that  a  larger  quantity  of  cheese 
is  obtained  per  100  parts  of  milk  when  pasteurized  milk  is 
used. 

6.  Destroys  Properties  of  Enzymes. — As  was  mentioned  in 
the  chapter  on  the  composition  of  milk,  there  is  a  substance  nor- 
mal to  milk  named  galactase.  This  is  an  enzyme.  By  heating 
milk  to  about  1750  F.  the  properties  of  the  enzyme  are  destroyed. 
Owing  to  this  it  is  easy  to  determine  whether  a  certain  sample  of 
milk  has  been  pasteurized  or  not.     Galactase  is  present  in  milk  in 

1  Exp.  Sta.  Record,  Vol.  15,  No.  10,  1904. 


42  PROPERTIES  OF  MILK 

so  small  a  quantity  that  it  cannot  be  determined  quantitatively, 
but  only  qualitatively. 

A  very  sensitive  and  reliable  test  for  determination  of  the 
efficiency  of  pasteurization  was  invented  by  Storch  a  number 
of  years  ago.  This  is  fully  described  in  Chapter  XV  on 
"  Pasteurization." 

7.  Divides  the  Clusters  of  Fat-globules. — The  fat-globules  in 
normal  milk  are  grouped  in  minute  clusters.  When  milk  is 
heated,  these  clusters  break  up,  and  each  globule  exists  more  or 
less  independently.  When  heated  to  an  excessively  high  tem- 
perature, and  exposed  to  this  temperature  very  long,  the  fat- 
globules  tend  to  run  together.  This  can  be  proved  by  heating 
milk  in  an  open  vat  for  about  half  an  hour.  A  small  amount  of 
yellow  fat  will  then  be  seen  floating  on  the  top. 

8.  Caramelizes  the  Sugar. — The  brownish  color  which  the 
milk  assumes  when  it  is  heated  excessively  is  due  to  a  change  which 
the  milk-sugar  undergoes.  Fleischmann  claims  that  the  sugar 
begins  to  change  into  a  substance  known  as  lacto-caramel  at  a 
temperature  of  1600  F.  This  change,  however,  is  not  pro- 
nounced enough  to  be  apparent  in  the  color,  unless  the  milk 
is  heated  a  long  time.  The  higher  the  temperature  is,  and  the 
longer  the  milk  is  exposed  to  the  heat,  the  more  pronounced  is 
the  change. 

General  Remarks. — While  all  of  the  above  changes  have 
been  found  by  investigators  to  take  place  when  milk  is  heated, 
they  can,  in  a  measure,  be  avoided,  if  special  precautions  are 
taken  in  the  heating  and  cooling  with  the  special,  recently 
improved  forms  of  apparatus  for  these  purposes. 

The  present  common  practice  of  heating  milk,  for  consump- 
tion as  such,  to  145 °  F.,  and  holding  at  this  temperature  for 
twenty  to  thirty  minutes,  is  accomplished  without  materially 
changing  its  chemical  or  physical  properties,  or  imparting  to  it  a 
flavor  that  is  at  all  objectionable. 


CHAPTER  IV 
MILK   AND   ITS   PRODUCTS   AS   FOODS 

HIGH  VALUE  OF  MILK-FAT 

There  are  two  methods  for  the  classification  of  foodstuffs  for 
animals  and  man,  and  both  of  these  will  be  briefly  considered  in 
this  chapter,  with  special  reference  to  milk  and  its  constituents — 
particularly  milk-fat — as  not  only  valuable  but  indispensable 
parts  of  the  dietary. 

The  older  method  may  be  spoken  of  as  the  chemical  method. 
It  considers  and  classifies  foods  largely  in  accordance  with  their 
content  of  water,  protein,  carbohydrates,  fats  and  mineral  matter. 
This,  in  itself,  is  quite  incomplete,  as  will  be  shown  later. 

The  newer  method,  which  is  known  as  the  biological  method, 
is  based  upon  a  study  of  the  properties  and  values  of  the  different 
foodstuffs,  through  feeding  them  and  noting  their  effect  upon 
growth,  health  and  reproduction .  This  method,  though  compara- 
tively new,  has  made  very  rapid  strides,  and  has  established  the 
fact  that  food  constituents  which  come  under  the  same  chemical 
head  are  by  no  means  either  alike  or  of  equal  nutritive  value. 

There  is  neither  the  hope  nor  the  expectation  that  the  bio- 
logical will  supersede  the  chemical  classification  of  foods  and 
foodstuffs,  in  the  sense  of  dispensing  with  the  aid  of  chemistry. 
The  true,  unbiased  student  of  the  problems  of  nutrition  recognizes 
two  things;  first,  that  the  chemical  method  has  rendered  and 
will  continue  to  render  a  very  large  service,  and,  second,  that  in 
itself  it  is  too  mechanical  and  incomplete. 

In  the  last  analysis,  the  biological  classification  of  foodstuffs 
must  prevail,  but  this  does  not  mean  that  it  and  chemistry  are 
at  variance  with  each  other.  Rather  it  means  that  there  must 
be  a  merging  of  the  chemical  into  the  larger  or  biological  method, 
and  that  in  future  a  larger,  fuller,  more  intelligent  and  less 

43 


44  MILK  AND  ITS  PRODUCTS  AS   FOODS 

mechanical  use  will  be  made  of  chemistry  as  an  aid  in  deter- 
mining the  values  of  the  different  foodstuffs  and  how  they  may 
best  be  combined  with  each  other  in  the  compounding  of  more 
economical  and  complete  rations  and  diets  on  which  animals  and 
man  will  grow  and  thrive.  At  times  the  biological  study  of  food- 
stuffs may  move  in  advance  of  chemistry,  as  it  has  already  done 
in  discovering  the  presence  in  milk-fat  of  a  fat-like  or  fat-soluble 
substance,  as  yet  unidentified,  which  renders  this  fat  altogether 
superior  to  other  animal  and  vegetable  fats  lacking  this  growth 
and  health -promoting  foodstuff.  It  is  the  province  of  chemistry 
to  ascertain,  if  possible,  what  this  substance  is.  The  same  may 
be  said  of  a  water-soluble  substance  which  is  not  nearly  so  limited 
as  to  its  sources,  being  present  in  sufficient  quantity  in  cereal 
grains  and  most  of  the  mixed  diets. 

CHEMICAL    CLASSIFICATION    OF    MILK    AND    ITS    PRODUCTS 

AS    FOODS 

From  the  chemical  standpoint,  the  constituents  of  the  food 
material  consumed  by  animals  and  man  are  classified  under  the 
heads  of  water,  combustible  matter  and  ash,  mineral  matter  or 
salts — all  three  terms  being  applied  to  the  last  class. 

The  combustible  matter  includes  the  carbohydrates  (such  as 
starches  and  sugars),  the  fats  (such  as  milk-fat,  olive  oil  and 
other  plant  oils,  and  meat-fat),  and  the  proteins  (such  as  the  curd 
of  milk,  the  gluten  of  wheat  and  the  muscle  fiber  of  lean  meat). 

The  carbohydrates  and  fats  are  largely  burned  to  supply 
heat  and  energy,  and  are  also  used  for  the  making  of  fat  in  the 
body  and  in  milk. 

The  proteins  are  used,  in  part,  for  the  same  purposes  as  the 
carbohydrates  and  fats,  but  their  distinct  function,  which  these 
latter  cannot  perform,  is  that  of  supplying  material  for  the 
making  of  muscle  and  other  body  tissue,  and  the  protein  of  milk. 

The  ash  or  mineral  matter  is  used  for  making  bone,  regulating 
the  heart  action  and  the  elasticity  of  the  muscles  in  general,  and 
preventing  acidity  of  the  blood  and  tissues. 

Under  the  older  classification  of  foods  we  find  that  milk 


BIOLOGICAL   CLASSIFICATION  OF  FOOD  45 

and  its  products  are  given  a  very  high  place,  on  account  of  their 
high  content  of  the  different  foodstuffs  or  constituents,  and  their 
high  degree  of  digestibility.  A  quart  of  average  milk  is  consid- 
ered by  such  high  authorities  as  Sherman  of  Columbia  University 
to  be  approximately  equal  in  food  value  to  a  pound  of  steak, 
or  eight  or  nine  eggs.  He  is  here  referring  chiefly  to  their  heat 
and  energy  value  and  high  degree  of  digestibility. 

American  cheese  (a  Cheddar  cheese)  may  be  regarded,  in  a 
very  large  sense,  as  a  concentrated  form  of  milk,  as  it  contains 
most  of  the  milk  constituents,  excepting  the  sugar.  It  has  about 
twice  the  food  value  of  average  meat.  On  this  point  Sherman 
says  "  Generally  speaking,  cheese  sells  at  no  higher  price  than 
the  ordinary  cuts  of  meat.  It  is  a  fair  general  estimate  that  a 
given  amount  of  money  spent  for  American  cheese  will  buy  about 
twice  as  much  food  value  as  it  would  if  spent  for  meat." 

Altogether  apart  from  a  distinctive  and  most  important 
function  which  will  be  considered  later,  butter  has  a  very  high 
heat  and  energy  value — a  pound  being  equal  to  about  five 
quarts  of  average  milk.  It  is  by  no  means  merely  a  relish,  as  it 
has  in  the  past  been  considered  by  many. 

We  cannot  here  afford  the  space  to  discuss  the  food  values  of 
the  various  other  milk  products,  such  as  cream,  ice-cream  and 
condensed  milk.  It  will  suffice  to  say  that  cream  occupies  an 
intermediate  position  between  milk  and  butter,  combining  the 
features  of  both. 

BIOLOGICAL  CLASSIFICATION  OF  FOODS 

The  High  Value  of  Milk  and  Milk-fat  under  this  Classification 

The  biological  study  of  foods — based  upon  observations  as  to 
the  influence  of  various  foodstuffs  upon  the  growth  and  thrift  of 
animals — has  revolutionized  our  ideas  with  regard  to  problems 
of  nutrition,  and  has  established  the  fact  that  the  biological 
classification  of  foods  is  the  true  one.  In  doing  so  it  has  shown 
that  milk  and  milk-fat  have  values  as  foods  which,  a  few  years 
ago,  were  quite  unknown,  and  which  as  yet  have  not  been  deter- 
mined chemically — or  at  least  have  been  determined  only  in  part. 


46  MUX  AND  ITS  PRODUCTS  AS  FOODS 

It  was  but  natural  that  biological  students  of  the  problems 
of  nutrition  should  give  their  attention  to  milk  and  endeavor  to 
ascertain  wherein  its  different  constituents  excelled  the  corre- 
sponding constituents  of  other  foods.  Knowing  that  the  young 
grow  and  thrive  on  a  diet  composed  exclusively  of  milk,  they 
realized  that  this  food  must  contain  nutritive  material  of  an 
exceptionally  high  order. 

Proteins 

The  proteins  of  plants  differ  from  those  of  animals  and  of  each 
other.  Animals  do  not  take  the  proteins  of  their  foods,  whether 
of  plant  or  animal  origin,  and  use  them  as  such,  without  any 
change.  In  the  processes  of  digestion  and  assimilation^  animals 
break  proteins  up  into  the  simpler  substances,  amino-acids,  and 
from  these  build  up  the  proteins  of  the  muscle  and  other  tissues 
of  the  body. 

There  are  eighteen  amino-acids  that  are  considered  in  nutri- 
tion problems.  The  protein  of  wheat  (gluten)  is  able  to  supply 
only  a  limited  number  of  these  in  sufficient  quantity,  and  some 
not  at  all.  The  proteins  of  the  corn  kernel  (zein,  etc.)  are 
able  to  supply  others,  and  so  on  with  the  proteins  of  the  different 
foods ;  but  none  of  these  is  a  complete  protein  food  for  the  animal 
body.  The  chief  protein  of  milk  (casein)  is,  however,  an  excep- 
tion, being  a  very  complete  and  well-balanced  protein,  which  is 
able  to  supply  the  different  amino-acids  in  sufficient  quantities 
and  right  proportions  to  build  up  muscle  and  other  protein 
tissue  of  the  body.  Thus  we  would  say  that  milk  furnishes  pro- 
tein of  a  quality  quite  superior  to  that  of  almost  any  other  food. 
This  we  see  exemplified  in  the  fact  that  the  young  animal  lives, 
grows  and  thrives  on  milk  alone. 

Ash  or  Mineral  Matter 

In  the  ash  or  mineral  matter  of  the  food  there  must  be  a 
sufficiency  of  such  elements  as  sodium,  potassium,  calcium, 
magnesium,  iron,  etc.,  in  the  form  of  inorganic  salts.  These 
perform  very  important  functions.  Each  has  its  work  to  do, 
and  they  are  not  interchangeable. 


BIOLOGICAL  CLASSIFICATION  OF  FOODS  47 

In  a  mixed  diet,  there  is  usually,  but  not  always,  a  sufficiency 
of  the  compounds  of  the  different  elements  mentioned.  We 
quote  Sherman  upon  this  point:  "  There  must  also  be  main- 
tained in  the  body  a  proper  balance  between  sodium  and  calcium 
(the  metal  of  lime).  For  example,  the  rhythmical  contraction 
and  relaxation  of  heart  muscle,  which  constitutes  the  normal 
beating  of  the  heart,  is  dependent  upon  this  muscle  being  bathed 
by  a  fluid  containing  the  proper  concentration  and  quantitative 
proportions  of  sodium  and  calcium.  Calcium  is  not  always  suf- 
ficiently abundant  even  when  the  food  is  freely  chosen;  hence  the 
richness  of  a  food  in  calcium  is  a  factor  affecting  its  value."1 
McCollum  and  Simmonds  found  as  a  result  of  their  experiments, 
"  that  the  deficiency  in  mineral  elements  in  wheat  and  other  seeds 
is  limited  to  three  elements,  calcium,  sodium  and  chlorine."2 

The  ash  of  milk  is  present  in  liberal  quantity,  is  of  high  qual- 
ity and  well  balanced,  and  is  rich  in  its  lime  content  as  a  source 
of  calcium.  There  is  more  lime  in  a  pint  of  milk  than  in  a  pint  of 
limewater. 

Two  Unidentified  but  Essential  Food  Substances — One  of  These 
in  Milk-fat  but  not  in  Ordinary  Fats 

There  are,  in  association  with  some  of  the  foodstuffs,  sub- 
stances which  have  not  as  yet  been  identified  chemically,  pos- 
sibly on  account  of  the  minute  quantities  in  which  they  are 
present;  and  yet  observation,  in  feeding  experiments,  has  shown 
that  they  are  indispensable.  If  these  are  absent  from  their 
foods,  animals  will  neither  grow  nor  retain  vigor. 

As  early  as  1906,  Hopkins  of  Cambridge  (England)  showed 
conclusively  that  on  an  apparently  complete  food  made  up  of 
purified  proteins,  ordinary  fats,  carbohydrates  and  salts  young 
rats  would  not  grow,  but  that  when  a  very  small  amount  of  milk 
was  used — enough  to  make  up  about  4  per  cent  of  the  dry  matter 
of  the  food — growth  became  entirely  satisfactory.  This  led  him 
to  conclude  that  there  were  present  in  milk  unidentified  food 
substances  which  he  termed  "  accessory  "  articles  of  the  diet. 

1  Food  Products,  pp.  19  and  20. 

2  The  Newer  Knowledge  of  Nutrition,  p.  23. 


48  MILK   AND   ITS  PRODUCTS   AS    FOODS 

These  would  be  what  McCollum  terms  the  "  fat-soluble  A," 
which  is  found  in  milk -fat  but  not  to  any  appreciable  extent  in 
the  ordinary  fats,  and  the  "  water-soluble  B,"  which  is  more 
generally  distributed  in  foods,  particularly  in  diets  of  mixed 
foods. 

Bloch,  a  Danish  physician,  observed  about  forty  cases  of 
severe  eye  trouble,  accompanied  by  ulceration,  in  children  near 
Copenhagen.  This  would,  without  doubt,  have  ended  in  blind- 
ness. These  children  had  been  receiving  skim-milk,  instead  of 
whole  milk,  in  their  diet,  and  were  practically  deprived  of  milk- 
fat  in  their  food.  When  the  younger  of  them  were  given  mother's 
milk,  and  the  older  either  cow's  milk  or  cod  liver  oil,  they 
responded  and  recovered.  He  attributed  the  trouble  to  the  lack 
of  fat  in  their  foods ;  but  it  will  be  noted  that  in  all  cases  the  real 
cause  of  recovery  was  the  feeding  of  fats  containing  the,  as  yet, 
unidentified  fat-soluble  which  is  present  in  the  fats  of  milk,  the 
yolk  of  egg,  the  liver  and  other  body  glands,  and  the  leaves  of 
plants,  particularly  such  plants  as  alfalfa  and  the  clovers. 

Mori  found  fourteen  hundred  cases  of  similar  eye  trouble 
amongst  children  in  Japan;  these  responded  to  the  feeding  of 
chicken  livers. 

It  has  been  found  both  by  McCollum  and  Davis,  and  by 
Osborne  and  Mendel  that  milk-fat  contains  a  fat-like  or  fat- 
soluble  substance  whose  presence  or  absence  in  a  food,  otherwise 
entirely  satisfactory,  means  the  difference  between  growth  and 
no  growth  in  the  young.  In  addition  to  this,  both  these  pairs  of 
investigators  found  that,  deprived  of  such  a  fat  as  milk-fat,  the 
young  animal  would  develop  a  disease  of  the  eyes  which  would 
ultimately  cause  blindness  and,  if  persisted  in,  would  end  in 
death;  but  that  if  this  fat  were  restored  in  time  the  eyes  would 
become  normal  again  and  the  young  animal  would  return  to  its 
former  health  and  vigor  and  resume  normal  growth. 

It  would  be  unfair  to  credit  any  one  man,  or  set  of  men 
collaborating  with  each  other,  with  the  discoveries  that  have 
been  made  during  the  past  fifteen  or  twenty  years — and  par- 
ticularly within  more  recent  years — through  the  biological  study 
of  foods.     The  list  of  investigators  is  rather  a  formidable  one. 


BIOLOGICAL  CLASSIFICATION  OF  FOODS  49 

and,  as  has  already  been  indicated,  includes  students  of  the  sub- 
ject extending  from  America  to  Europe  and  even  to  far-away 
Japan.  Without  doubt  the  best  known  of  these  in  America  Is 
Dr.  E.  V.  McCollum,  whose  extensive  and  most  valuable  articles 
appeared  in  Hoard's  Dairyman  and  other  farm  and  scientific 
journals,  and  who  has  issued  a  valuable  book  on  the  subject, 
entitled,  "  The  Newer  Knowledge  of  Nutrition."  In  this  book 
he  outlines  the  investigations  conducted  by  him  and  his  co- 
workers— Babcock,  Hart,  Davis,  Steinbeck,  Humphrey,  Parsons, 
Funk,  Kennedy,  Simmonds  and  Pitz — and  also  familiarizes  us 
with  the  work  of  many  other  investigators. 

As  McCollum  intimates,  in  order  to  secure  reliable  and  exact 
data  it  was  necessary  to  feed  purified  foodstuffs  (purified  protein, 
carbohydrates,  fats  and  mineral  salts),  and  in  order  to  do  this 
and  secure  sufficient  data  within  a  reasonable  time  it  was  neces- 
sary to  experiment  with  small  animals.  For  these  reasons, 
the  experiments  were  conducted  mostly  with  young  rats,  although 
like  results  were  also  obtained  with  other  animals,  including 
cattle  and  pigs.  Accumulated  data,  from  a  variety  of  sources , 
show  that  the  results  secured  are  equally  applicable  to  the  different 
animals,  including  man. 

In  one  of  the  earlier  experiments  with  rats,  conducted  by 
McCollum  and  Davis,  they  fed  a  diet  composed  of  purified  pro- 
tein (casein)  to  the  extent  of  18  per  cent,  lactose  or  milk-sugar 
20  per  cent  (supposed  to  be  pure),  about  5  per  cent  of  some  fat, 
together  with  a  salt  mixture  made  up  in  imitation  of  the  mineral 
matter  of  milk,  and  the  balance  of  starch  to  make  up  100  per  cent. 
The  results  of  this  experiment  were  that  when  the  fat  used  was 
milk-fat  growth  could  be  secured,  but  that  when  this  was 
replaced  by  such  fats  as  lard,  olive  oil  or  other  vegetable  oils, 
there  was  no  growth.  When  the  fat  of  yolk  of  egg  was  used 
instead  of  milk-fat  it  also  induced  growth.  These  experiments 
established  the  fact  that  fats  from  different  sources  are  by  no 
means  equal  in  dietary  value. 

Following  this  a  more  elaborate  experiment  was  planned  and 
carried  out  by  McCollum  and  Davis.  It  will  be  noted  that  the 
diet  of  purified  foodstuffs,  which  proved  a  satisfactory  one,  was 


50  MILK   AND   ITS   PRODUCTS  AS   FOODS 

made  up  of  purified  milk  constituents.  McCollum  and  Davis 
next  tried  the  wheat  seed  or  kernel.  They  reasoned  that  it  con- 
tained protein,  carbohydrates  and  mineral  salts  and  fats  or  oil, 
and  that  if  these  were  mostly  equal  in  quality  to  those  of  milk 
the  only  foodstuff  that  might  have  to  be  added  would  be  a  growth- 
promoting  fat.  They  first  fed  wheat  alone  and  then  tried  the 
improvement  of  it  with  respect  to  one  dietary  factor  at  a  time. 
The  following  indicates  the  different  combinations  in  which 
wheat  was  fed,  with  results  secured: 

(i)  Wheat  alone No  growth,  short  life. 

(2)  Wheat,  plus  purified  protein No  growth,  short  life. 

(3)  WTheat  plus  a  salt  mixture  which  gave  it  a 

mineral  content,  similar  to  that  of  milk  Very  little  growth        t 

(4)  Wheat  plus  a  growth-promoting  fat  (milk- 

fat)  No  growth. 

(5)  WTheat,  plus  the  protein,  plus  the  salt  mix- 

ture  Good  growth  for  a  time,  few  or  no 

young,  short  life. 

(6)  Wheat,  plus  protein,  plus  a  growth-pro- 

moting fat  (milk-fat) No  growth,  short  life. 

(7)  Wheat,   plus  the  salt  mixture,   plus  the 

growth-promoting  fat  (milk-fat) Fair  growth  for  a  time,  few  or  no 

young,  short  life. 

(8)  Wheat,  plus  protein,  plus  the  salt  mixture, 

plus  a  growth-promoting  fat  (milk-fat)  Good   growth,  normal   number   of 

young,    good  success    in    rearing 

young;     life  approximately    the 
normal  span. 

This  series  of  experiments  again  proves  the  necessity  of  a 
growth-promoting  fat.  But  it  does  more  than  this;  it  shows  that 
the  proteins  and  mineral  matter  from  different  sources  are  not 
of  equal  value,  those  of  milk  being  altogether  superior  in  this 
respect  to  those  of  such  a  food  as  wheat.  Other  experiments 
proved  that  the  seeds  of  other  cereals  are,  like  wheat,  quite 
incomplete  in  themselves  as  diets. 

In  following  up  this  investigation  it  was  found  that  when 
polished  rice  was  substituted  for  wheat,  in  No.  8  of  the  series  of 
experiments  just  outlined,  the  diet  failed  utterly  to  induce 
growth.  This  was  puzzling.  The  investigators  had  been  able 
to  induce  successful  growth  through  feeding  a  diet  composed  of 


BIOLOGICAL  CLASSIFICATION  OF   FOODS  51 

purified  protein  (casein),  milk-sugar  (supposedly  pure),  salts  in 
imitation  of  the  mineral  matter  of  milk,  and  milk-fat.  They 
could  see  no  reason  why  the  polished  rice,  supplemented  by  puri-- 
fied  protein,  suitable  salts  and  milk-fat  should  not  be  a  complete 
food.  This  was  cleared  up  subsequently  by  establishing  the 
fact  that  the  milk-sugar  used  in  the  former  of  these  two  experi- 
ments, and  the  germ  or  chit  of  the  cereal  seeds,  which  had  been 
rubbed  off  the  rice,  contain  a  water-soluble  substance  essential  for 
growth,  health  and  vigor. 

The  conclusions  finally  reached  were,  first,  that  amongst 
the  food  substances  (protein,  carbohydrates  and  ash  or  mineral 
matter)  coming  from  different  sources  there  is  a  marked  differ- 
ence in  quality,  and  that  those  from  milk  are  of  a  very  high  order; 
and  second,  that  there  are  two  as  yet  unidentified  substances 
which  are  indispensable  to  growth  and  health,  namely,  the 
unknown  substance  which  is  present  in  milk-fat,  the  fat  of  yolk  of 
egg  and  some  of  the  glandular  fats,  which  McCollum  and  Ken- 
nedy subsequently  designated  "  fat-soluble  A,"  and  a  second 
substance  soluble  in  water,  which  they  designated  "  water- 
soluble  B."  The  absence  of  the  former  (fat-soluble  A)  not  only 
prevents  growth,  but  also  causes  a  serious  eye  trouble  which,  if 
not  corrected  in  time,  will  end  in  blindness  and  death.  We  have 
already  illustrated  this  point.  The  absence  of  the  water- 
soluble  also  prevents  growth,  and  causes  serious  physiological 
disturbances  resulting  in  a  form  of  paralysis,  beri-beri,  which  is 
quite  prevalent  where  such  foods  as  polished  rice  and  bolted 
flour  form  the  main  article  of  diet. 

But  this  water-soluble  is  present  in  most  ordinary  food 
substances,  and  particularly  in  a  mixed  diet,  whereas  the  sources 
of  the  fat-soluble  are  quite  limited,  the  fat  of  milk,  in  the  form 
of  milk  and  butter,  being  the  chief  of  these. 

In  support  of  what  has  been  said,  the  utterances  of  some  of 
our  leading  physiologists  and  students  of  nutrition  may  be 
quoted. 

Dr.  H.  C.  Sherman,  Professor  of  Food  Chemistry,  Columbia 
University:  "  Especially  in  the  feeding  of  children  should  milk 
be  used  freely,  because  of  its  many  advantages  as  a  tissue- 


52  MILK  AND   ITS   PRODUCTS  AS   FOODS 

building  and  growth-promoting  food.  A  quart  of  milk  a  day 
for  every  child  is  a  good  rule  easy  to  remember." 

United  States  Food  Administration:  "  Milk  is  one  of  the  most 
important  food  sources  the  human  race  possesses.  For  the 
proper  nourishment  of  the  child  it  is  absolutely  indispensable 
and  its  use  should  be  kept  up  in  the  diet  as  long  as  possible.  Not 
only  does  it  contain  all  the  essential  food  elements  in  the  most 
available  form  for  ready  digestion,  but  the  recent  scientific  dis- 
coveries show  it  to  be  especially  rich  in  certain  peculiar  properties 
that  alone  render  growth  possible.  This  essential  quality  makes 
it  also  of  special  value  in  the  sick  room.  In  hospitals  it  has  also 
been  shown  that  the  wounded  recover  more  rapidly  when  they 
have  milk.  » 

"  For  the  purpose  of  stimulating  growth,  and  especially  in 
children,  butter-fat  and  other  constituents  of  milk  have  no 
substitutes." 

Dr.  E.  V.  McCollum,  Johns  Hopkins  University:  "  I  have 
come  to  the  conclusion,  after  carefully  analyzing  the  probable 
effectiveness  of  the  combinations  of  foods  employed  in  human 
nutrition,  that  the  efficiency  of  a  people  can  be  predicted  with 
a  fair  degree  of  accuracy  from  a  knowledge  of  the  degree  to  which 
they  consume  dairy  products.  Probably  the  use  of  meat  and  of 
milk  and  its  products  will,  in  nearly  all  cases,  run  more  or  less 
nearly  parallel,  and  I  venture  to  assert  that  it  is  the  milk  and 
butter  and  cheese,  and  not  the  meat  which  has  the  good  influence 
in  the  promotion  of  the  virile  qualities  of  the  people. 

"  Milk  is  worth  much  more  than  its  energy  value  or  than  its 
protein  content  would  indicate.  It  is  the  great  factor  of  safety 
in  making  up  the  deficiencies  of  the  grains  which  form  and  must 
continue  to  form  the  principal  source  of  energy  in  our  diet. 

"  It  seems  probable  that  the  only  unidentified  substance 
which  is  physiologically  indispensable,  which  is  not  sufficiently 
abundant  in  the  diets  employed  by  the  people  of  the  United 
States  and  Europe  where  there  are  used  insufficient  amounts  of 
milk,  butter,  cream,  eggs  and  the  leafy  vegetables,  is  the  fat- 
soluble  A." 

"  I  wish  to  again  emphasize  the  fact  that  there  is  no  way  to 


BIOLOGICAL  CLASSIFICATION  OF  FOODS  53 

supply  this  dietary  factor  (fat-soluble  A)  in  the  food  of  children 
except  in  the  form  of  milk-fat,  and  milk  is  therefore  an  indis- 
pensable food  for  the  young."  —  - 
Attention  should  be  called  to  one  other  point.  It  has  been 
suggested  by  some  that  possibly  pasteurization  of  milk  or  cream 
destroys  the  growth-promoting  qualities  of  the  "  fat-soluble  A  " 
in  the  fat.  Osbourne  and  Mendel  found  that  passing  live  steam 
through  milk-fat  for  two  hours  did  not  affect  it,  and  McCollum 
and  Davis  found  that  it  was  not  affected  by  being  heated  to 
the  boiling-point  of  water.  This  should  be  satisfactory  evidence 
that  pasteurization  of  milk  or  cream  in  no  way  affects  the  growth- 
promoting  qualities  of  the  milk-fat. 


CHAPTER  V 
FERMENTS  IN  MILK 

Definition.  —  The  changes  which  milk  undergoes  when 
allowed  to  stand  at  a  suitable  temperature  are  commonly  called 
fermentations,  and  the  agencies  which  bring  about  these  changes 
are  called  ferments.  At  one  time  the  ferments  were  classified 
under  two  heads,  viz.,  organized  ferments  (bacteria,  yeasts 
and  molds),  and  enzymes  or  unorganized  ferments,  such  as  those 
found  in  rennet  and  other  fluids  in  the  digestive  tracts  of  animals. 
This  distinction  is  no  longer  made,  since  bacteriologists  and 
physiological  chemists  have  reached  the  conclusion  that  the 
fermentative  changes,  due  to  the  action  of  germ  life,  are  caused 
by  enzymes  which  these  micro-organisms  produce.  However, 
the  enzymes  themselves  may,  from  a  dairy  standpoint,  be  classi- 
fied as  follows: 

(i)  The  pre-existing  enzymes  of  milk,  or  those  which  are 
formed  during  milk  secretion  and  consequently  are  in  the  milk 
when  it  is  drawn  from  the  cow.  The  first  of  these  was  dis- 
covered by  Babcock  and  Russell  of  the  Wisconsin  Station,  in 
1889,  and  was  named  galactase  by  the  discoverers.  It  is  a 
tryptic  ferment.  Since  then  others,  such  as  catalase  and  peroxi- 
dase, have  been  discovered.  It  would  seem,  from  investigations 
made  by  Russell  and  Babcock,  that  the  inherent  enzymes  of 
milk,  which  are  digesting  ferments,  are  essential  to  and  play  an 
important  role  in  the  ripening  of  the  Cheddar  type  of  cheese. 
They  find  that  it  is  impossible  to  produce  a  typical,  normal 
Cheddar  cheese  from  thoroughly  pasteurized  milk.  According 
to  S torch,  the  peroxidase  has  the  power  of  decomposing  hydrogen 
peroxide  and  setting  free  "  active  "  oxygen.  As  this  ferment  is 
not  destroyed  until  milk  or  cream  is  heated  to  a  high  temperature, 

54 


FAVORABLE   CONDITIONS   FOR  BACTERIAL   GROWTH       Zu 

it  forms  the  basis  for  the  Storch  test  for  the  efficiency  of  the  pas- 
teurization of  milk  or  cream  for  butter-making.  This  test  is 
described  in  the  chapter  on  Pasteurization. 

(2)  Enzymes  developed  through  the  action  of  germ  life — 
bacteria,  yeasts  and  molds.  These  are  many  and  varied,  and 
cause  most  of  the  changes  that  take  place  in  milk  and  its  products, 
such,  for  example,  as  the  ordinary  souring  of  milk  or  cream,  and 
the  development  of  flavor  and  aroma  in  cream  ripening. 

(3)  Enzymes  found  in  the  digestive  fluids  of  animals.  All  are 
familiar  with  the  fact  that  rennet  is  used  in  cheese-making.  It 
contains  a  ferment  known  as  rennin. 

It  is  the  second  class  of  ferments  or  enzymes,  the  class  due  to 
the  action  of  germ  life  (principally  bacteria) ,  which  is  of  the  great- 
est importance  in  connection  with  dairying,  and  with  the  control 
of  which  the  dairyman  concerns  himself  most.  These  ferments 
are  capable  of  working  profound  changes,  some  desirable  and  some 
very  undesirable. 

Size  and  Shape  of  Bacteria. — In  size,  bacteria  are  the  smallest 
organisms  that  exist,  so  far  as  known.  The  size  varies  consider- 
ably. Russell 1  gives  the  average  diameter  as  30000  of  an  inch. 
They  are  so  inconceivably  small  and  light  that  nine  hundred 
billions  of  them  would  only  weigh  ■£$  of  an  ounce.2 

Bacteria  also  vary  considerably  in  shape.  They  are  as  a 
rule  classed  into  three  groups:  (1)  The  bacillus  or  rod-shaped; 
(2)  The  coccus  or  ball-shaped;  (3)  The  spirillum  or  spiral-shaped 
(like  a  corkscrew).  Some  types  of  bacteria  are  classified  accord- 
ing to  the  way  in  which  they  adhere  to  each  other.  For  instance, 
when  two  cocci  occur  together  and  form  a  pair,  they  are  called 
diplococci;  when  cocci  occur  in  chains,  they  are  called  strepto- 
cocci; when  cocci  appear  in  bunches,  they  are  called  staphylo- 
cocci, etc. 

FAVORABLE  CONDITIONS  FOR  BACTERIAL  GROWTH 

Food. — Bacteria,  like  other  plants,  need  food  for  their  exist- 
ence. The  food  passes  into  the  bacterial  cell  in  solution,  but 
many  organisms  use  materials  not  in  solution  by  producing 

1  Dairy  Bacteriology.         2  Milk,  Its  Nature  and  Composition,  by  Aikman. 


56  FERMENTS  IN  MILK 

enzymes  that  dissolve  them.  Nitrogen,  carbon,  oxygen,  hydro- 
gen and  mineral  matter  are  essentials  for  bacteria.  These  sub- 
stances are  furnished  in  abundance  in  milk  from  casein,  albumen, 
milk-sugar,  and  the  mineral  salts.  Butter-fat  in  milk  is  said  to  be 
of  little  value  as  a  food  for  bacteria. 

Some  organisms,  including  yeasts  and  molds,  tolerate  con- 
siderable amounts  of  acid,  while  others  do  not.  Most  bacteria, 
however,  prefer  a  neutral  or  slightly  alkaline  substance.  Dark- 
ness is  essential  to  some  bacteria,  and  is  preferred  by  the  majority 
of   the  different  species.     Bright  sunlight  is  a  very  effective 


Fig.  7. — <z,  single  bacterium;  b,  progeny  resulting  from  the  growth  of  a  bacterium 
during  24  hours  in  milk  at  500  F.;  c,  progeny  of  a  bacterium  during  24  hours 
growth  in  milk  at  700  F.  At  500  F.  multiplication  was  5-fold.  At  700  F. 
the  multiplication  was  750-fold.     (Bui.  26,  Storrs,  Conn.) 

germicide;  it  is  fatal  to  all  species,  so  far  as  known.  Some  germs 
require  air  for  their  growth.  These  are  called  aerobic.  Others 
again  grow  only  in  the  absence  of  air.  These  are  called  anaerobic. 
Some  grow  under  either  or  both  conditions,  and  are  called 
facultative. 

Temperature. — Favorable  temperature  is  essential  to  bac- 
terial growth.  Temperature  is,  indeed,  the  most  important 
means  by  which  the  growth  and  development  of  bacteria  can  be 
controlled.  The  range  of  temperature  at  which  bacterial 
growth  is  likely  to  occur  may  be  placed  between  freezing-point  and 
a  little  above  no°  F.     There  are,  however,  exceptions  to  this 


FAVORABLE  CONDITIONS  FOR  BACTERIAL  GROWTH 


57 


range.     Some  few  species  will  grow  at  as  high  a  temperature  as 
1400  F.,  and  B.  bulgaricus  will  grow  very  rapidly  at  no°  F. 

The  growth  of  bacteria  at  these  extreme  temperatures  4s 
usually  very  slight.  Even  at  500  F.  the  rate  of  growth  is  very 
slow.  According  to  experiments  conducted  by  Dr.  Conn,  the 
multiplication  of  bacteria  at  500  F.  was  5-fold,  while  at  700  F. 
the  multiplication  was  750-fold.  The  following  table  shows  the 
number  of  bacteria  per  cubic  centimeter  in  milk  kept  at  different 
temperatures.1 


No.  at 
Outset 


46,000 
47,000 

50,000 


In  12  . 

In  12 

In  50 

Hours 

Hours 

Hours 

at5o° 

at  700 

at  500 

39,000 

240,500 

1,500,000 

44,800 

360,000 

127,500 

35>°°o 

800,000 

160,000 

In  50  Hrs. 

No.  of 

or  at  Time 

Hours  be- 

of Curd- 

fore Curd- 

ling  at  700 

ting  at  500 

542,000,000 

190 

7Q  2, 000,000 

289 

36  hours 

2,560,000,000 

172 

42  hours 

No.  of 
Hours  be- 
fore Curd- 
ling at  700 

56 
36 

42 


All  bacteria  do  not  have  the  same  optimum  growing  tem- 
perature. Some  species  develop  most  rapidly  at  one  tempera- 
ture, while  other  species  prefer  a  different  temperature  for  the 
greatest  development.  It  is  on  this  account  that  certain  tem- 
peratures are  employed  in  ripening  starters  and  cream.  Accord- 
ing to  researches  by  Conn,  Bacterium  aerogenes  develops  very 
rapidly  in  milk  at  95 °  F.  This  particular  species,  producing 
much  gas  and  an  unpleasant  flavor,  sours  milk  very  rapidly.  As 
a  rule,  milk  which  has  been  held  at  this  high  temperature  con- 
tains a  preponderance  of  this  undesirable  species  of  bacteria. 
At  770  F.  results  are  more  uncertain;  the  species  of  bacteria 
which  will  predominate  in  milk  at  this  temperature  depends  in 
large  measure  upon  the  number  of  each  kind  originally  present. 
According  to  Conn  Streptococcus  lacticus  has  the  highest  relative 
growth  at  about  700  F.  This  particular  species  produces  no  gas, 
and  its  presence  is  desirable  in  cream  for  butter-making.     Milk 


1  Bull,  26  Storr's  Sta.,  Conn. 


58  FERMENTS  IN  MILK 

kept  at  this  temperature  will,  in  most  cases,  providing  it  has  pre- 
viously been  properly  treated,  develop  a  pleasant  acid  taste,  will 
curdle  into  a  smooth  uniform  coagulum,  and  will  contain  a  pre- 
ponderance of  the  species  of  germ  mentioned  above. 

At  as  low  a  temperature  as  500  F.  acid-producing  types  of 
bacteria  do  not  develop  very  well.  But  Conn  maintains  that 
miscellaneous  species  of  bacteria  that  produce  unfavorable 
results  develop  at  this  temperature.  While  milk  does  not  easily 
sour  at  this  temperature,  it  should  be  remembered  that  undesir- 
able germs  are  constantly  developing. 

As  it  is  practically  impossible  to  exclude  all  of  the  bacteria 
from  milk  during  milking  and  the  handling  of  the  milk,  it  is 
very  essential  that  the  multiplication  of  the  germs  present  be 
checked,  or  at  least  retarded;  and  this  can  be  done  by  controlling 
the  temperature  of  the  milk.  As  low  temperature  is  effective  in 
checking  the  multiplication  of  the  bacteria,  the  sooner  the  milk 
can  be  cooled  after  it  is  drawn,  the  better  it  will  be  likely  to  keep. 

Moisture. — Moisture  is  one  of  the  essentials  for  bacterial 
growth.  As  milk  is  composed  largely  of  water,  bacteria  find  in 
milk  a  good  medium  for  growth.  All  the  other  required  food 
elements  are  also  found  in  abundance  in  milk.  Damp  utensils 
and  rooms  are  always  more  conducive  to  the  growth  of  germs 
than  are  utensils  and  rooms  which  are  thoroughly  dried  and 
ventilated.  This  is  well  illustrated  by  a  refrigerator.  A  very 
damp  dark  refrigerator  is  always  more  conducive  to  the  growth 
of  molds  in  butter  than  is  a  dry  refrigerator. 

Unfavorable  Conditions  for  Bacterial  Growth. — The  reverse 
of  the  favorable  conditions  mentioned  above  would  be  unfavorable 
to  the  growth  of  bacteria.  As  it  is  practically  impossible  to  make 
conditions  unfavorable  for  the  growth  of  bacteria  by  taking 
away  food,  other  means  must  be  used.  Extremely  high  tem- 
peratures destroy  bacteria.  Low  temperatures  check  their 
growth,  but  so  far  as  known  do  not  destroy  them.  Absence  of 
moisture  and  presence  of  direct  sunlight  are  conditions  which  are 
not  conducive  to  bacterial  growth.  Certain  chemical  substances 
when  added  to  milk,  or  to  the  medium  in  which  the  bacteria  are 
present,  are  very  unfavorable  to  their  growth.     Some  of  these 


UNFAVORABLE  CONDITIONS   FOR  BACTERIAL  GROWTH      59 

chemicals  entirely  destroy  all  germ  life  even  when  added  in  very 
small  quantities.  These  are  called  disinfectants  (formaldehyde, 
corrosive  sublimate,  etc.).  Other  chemicals  are  more  mild  in 
their  effect  upon  germ  growth,  and  merely  inhibit  or  retard  the 
growth  of  micro-organisms.  The  chemicals  which  have  this 
milder  effect  upon  germs  are  called  antiseptics.  Boracic  and 
salicylic  acids  are  examples.     Practically  all  disinfectants  are 


Fig.  8. — Shows  a  plate  exposed  in  pasture  where  air  must  have  been  very  pure 
and  free  from  germs.     (Bui.  87,  Nebraska.) 

violent  poisons,  and  should  not  be  used  in  any  quantity  or  in 
any  form  in  milk  or  dairy  products  which  are  intended  for  human 
food.  The  milder  preservatives  or  the  antiseptics,  are,  as  a  rule, 
not  so  poisonous  or  injurious  to  human  health.  In  some  coun- 
tries they  are  allowed  to  a  small  extent.  For  instance,  according 
to  reports,  the  laws  of  England  permit  the  use  of  boracic  acid 
in  butter  to  the  extent  of  0.5  of  1  per  cent.  It  is,  however,  safest 
not  to  use  any  of  these  chemicals,  except  for  preserving  samples 


60  FERMENTS  IN  MILK 

for  analytical  or  similar  purposes.  As  low  and  high  tempera- 
tures are  so  effective  in  producing  unfavorable  conditions,  these 
should  be  chiefly  employed  in  controlling  the  growth  of  micro- 
organisms in  the  dairy  industry. 

Kind  of  Germs  Found  in  Milk. — The  number  of  species  of 
germs  found  in  milk  has  not  yet  been  definitely  established,  due 
chiefly  to  the  fact  that  it  is  in  some  instances  difficult  for  bacteri- 
ologists to  differentiate  one  species  from  another.     The  descrip- 


Fig.  9. — Shows  a  plate  exposed  one-half  minute  under  a  cow's  udder  treated  with  a 
5  per  cent  solution  of  carbolic  acid.     (Bui.  87,  Nebraska.) 

tion  of  one  species  of  bacteria  by  two  different  bacteriologists 
may  vary  considerably,  as  the  characteristics  of  the  germs 
depend  so  much  upon  the  conditions  prevailing  throughout  the 
classification  process.  Over  200  different  species  have  been 
described.  It  is  possible,  however,  though  all  of  these  types 
may  have  different  morphological  and  physiological  character- 
istics as  described  by  different  bacteriologists,  that  some  two  or 
more  of  the  200  types  may  belong  to  one  species. 


KIND  OF  GERMS  FOUND  IN  MILK 


(31 


For  this  purpose,  it  is  sufficient  to  classify  the  bacteria  into 
three  groups,  viz.,  (i)  those  which  are  harmful  to  the  butter- 
making  industry,  (2)  those  which  are  beneficial,  and  (3)  those 
which  are  indifferent,  or  produce  neither  good  nor  bad  results. 

From  the  farmer's  or  milk-producer's  standpoint,  none  of 
these  bacteria  are  desirable.  Each  milk-producer  should  make 
it  a  point  to  prevent  their  entrance  and  suppress  their  develop- 


Fig.  10. — Shows  plate  exposed  one-half  minute  under  cow's  udder  treated  by  merely, 
brushing  with  the  hand;  each  little  spot  represents  a  colony  of  some  kind  of 
bacteria.     (Bui.  87,  Nebraska.) 


ment  in  milk  and  cream  to  as  great  an  extent  as  possible.  The 
creamery  operator  should  endeavor  to  suppress  all  of  the  harmful 
germs,  and  foster  the  development  of  the  desirable  ones. 

The  germs  which  are  desirable  belong  to  the  acid-producing 
types,  such  as  Streptococcus  lacticus,  and  the  associated  flavor 
and  aroma-producing  types,  such  as  Streptococcus  citrovorus. 

The  harmful  bacteria  include  those  which  produce  bitter 
milk,  red  milk,  blue  milk,  yellow  milk,  slimy  milk,  gas,  and 


62  FERMENTS  IN  MILK 

undesirable  flavors  and  aromas.  There  are  a  number  of  species 
belonging  to  this  group.  The  pathogenic  germs,  or  disease- 
producing  bacteria,  must  also  be  classed  with  the  harmful  bac- 
teria. It  is  not  the  intention  in  this  work  to  give  an  extended 
discussion  of  this  subject.  For  such  discussion  see  special  works 
on  Dairy  Bacteriology. 

Number  of  Bacteria  in  Milk. — The  number  of  bacteria  found 
in  milk  varies  so  much  that  it  is  practically  impossible  to  state 
accurately  the  average  number.  The  number  of  germs  found 
varies  according  to  several  conditions,  such  as  degree  of  cleanli- 
ness of  cows,  utensils,  and  milker;  degree  of  purity  of  the  atmos- 
phere when  the  cows  are  milked;  the  temperature  at  which  the 
milk  is  kept  and  the  time  it  is  held.  When  the  milk  is  being 
produced  under  the  best  practical  sanitary  conditions,  the  number 
of  germs  need  not  exceed  10,000  per  cubic  centimeter.  Such 
results  cannot  be  obtained  unless  extreme  precautions  are  taken. 
Milk  produced  under  average  farm  conditions  seldom  contains 
less  than  50,000  germs  per  cubic  centimeter  shortly  after  the 
milking.  Milk  which  is  produced  under  filthy  conditions,  and 
which  is  several  hours  old,  may  contain  several  millions  of  bac- 
teria per  cubic  centimeter. 

Sources  of  Bacteria  in  Milk. — Bacteria  are  widely  distributed 
in  nature.  They  float  in  the  atmosphere  and  adhere  to  particles 
of  dust.  Especially  is  this  so  in  the  dusty  cow-stable.  They 
are  present  in  all  well  water  to  a  greater  or  less  extent,  and  are 
very  abundant  in  streams  and  rivers.  They  are  present  in  the 
soil  to  a  depth  of  several  feet,  the  number  decreasing  with  the 
depth.  As  these  germs  are  practically  present  everywhere,  the 
sources  of  germs  in  milk  may  be  said  to  be  all  around  us.  The 
principal  sources  of  germs  in  milk  are,  however,  unclean  dairy 
utensils,  unclean  cows,  and  unclean  surroundings.  As  these 
germs  multiply  chiefly  by  fission,  or  by  one  cell  dividing  into  two, 
it  is  plain  that  the  number  of  germs  will  increase  very  rapidly 
under  favorable  conditions.  Under  the  most  favorable  condi- 
tions it  requires  approximately  twenty  minutes  for  this  process  of 
fission  to  take  place. 

Some  germs  develop  small  bodies  within   the   cell,   called 


SOURCES  OF  BACTERIA  IN  MILK  63 

spores.  It  is  not  difficult  to  destroy  the  sporeless  cell  by  heat, 
but  the  spores  are  very  resistant  to  unfavorable  conditions. 
The  spore-bearing  bacteria  are  difficult  to  kill ;  boiling  for  a  short 
time  will  not  destroy  them.  Hammer  is  satisfied  that  they  are 
destroyed  by  prolonged  boiling.  Another  method  is  to  heat  the 
milk  to  destroy  all  the  organisms  in  the  vegetative  stage,  then 
cool  it  to  a  temperature  favorable  to  growth  and  allow  the  spores 
to  develop  into  the  vegetative  stage,  and  again  apply  heat.  In 
this  way  milk  can  be  rendered  entirely  sterile.     A  single  heating 


Fig.  ii. — The  wrong  and  the  right  kind  of  a  milk-pail.  A,  the  ordinary  type  of 
pail  showing  sharp  angle  between  sides  and  bottom;  B,  the  same  properly 
flushed  with  solder  so  as  to  facilitate  thorough  cleaning.  The  lower  figure 
represents  a  joint  as  ordinarily  made  in  tinware.  The  depression  a  affords 
a  place  of  refuge  for  bacteria  from  which  they  are  not  readily  dislodged.  This 
open  joint  should  be  filled  completely  with  solder.     (From  Bui.  62,  Wis.) 

under  pressure  (fifteen  minutes  at  1 5  pounds  pressure)  kills  them 
at  once. 

It  has  been  demonstrated  by  several  investigators  that  freshly 
drawn  milk  is  not  a  good  medium  for  bacteria  to  develop  in. 
In  fact,  several  experiments  seem  to  indicate  that  milk  acts  as  a 
germicide  to  certain  varieties  of  bacteria.  For  instance,  the 
cholera  germ  is  to  some  extent  destroyed  in  fresh  milk,  but  it  is  not 
known  to  what  extent.  Organisms  producing  lactic  acid  check 
the  multiplications  of  these  pathogenic  bacteria.  This  germicidal 
property  is  said  to  be  more  or  less  common  to  all  the  animal 
secretions. 


64  FERMENTS   IN   MILK 

Effect  of  Thunder-storms  on  Souring  of  Milk. — It  is  a  common 
impression  that  thunder-storms  hasten  the  souring  of  milk.  This 
was  attributed  to  the  electricity  in  the  air  accompanying  the 
storm.  Experiments  by  several  investigators  have  proved 
that  electricity  does  not  have  any  effect  on  hastening  the  fer- 
mentative changes  of  milk.  The  reason  why  milk  sours  more 
quickly  when  an  electrical  storm  is  approaching  is  that  the  air 
temperature  is  usually  higher  then  than  at  any  other  time.  This 
higher  temperature  warms  the  milk  and  creates  more  favorable 
conditions  for  the  rapid  multiplication  of  the  germs  present  in  the 
milk.  It  is  for  this  reason  that  milk  sours  more  quickly  during  or 
previous  to  a  thunder  storm  than  at  any  other  time. 


CHAPTER  VI 
ABNORMAL  MILK 

Colostrum  Milk. — Colostrum  is  the  milk  yielded  immediately 
after  calving.  As  the  time  of  calving  approaches,  a  cow  usually 
diminishes  in  her  milk-producing  capacity.  Most  cows  become 
dry  about  two  months  previous  to  parturition.  If  they  do  not 
naturally  stop  giving  milk,  they  should  be  dried  up  so  as  to  have 
a  seven  weeks'  rest  before  calving.  When  the  rest  has  been 
given,  the  cows  yield,  immediately  after  calving,  milk  which  has 
a  composition  and  characteristics  different  from  those  of  normal 
milk.  If  the  cow  continues  to  give  a  copious  flow  of  milk  up  to 
the  time  of  calving  and  is  not  allowed  any  rest,  the  difference  in 
the  milk  yielded  before  calving  and  after  calving  is  comparatively 
slight. 

The  composition  of  colostrum  varies  considerably  during  the 
first  three  days  after  calving.  According  to  Engling,  as  reported 
by  Richmond,  the  composition  is  as  follows: 

Per  Cent 

Water 7 1 .  69 

Fat 3.37 

.  „        .     » ,    J  Casein 4.83 

Albuminoids  i    .  „  ^° 

I  Albumen 15-85 

Sugar 2 .  48 

Ash 1 .  78 

Colostrum  greatly  changes  in  composition  and  appearance  as  it 
gradually  assumes  the  characteristics  of  normal  milk.  It  is  at 
first  reddish  yellow  in  color,  and  has  a  viscous  and  slimy  con- 
sistency. It  is  a  food  which  the  newly  born  calf  should  not  be 
deprived  of,  as  it  seems  to  be  specially  suited  for  the  digestive 
tract  of  the  young  calf. 

65 


66  ABNORMAL  MILK 

It  will  be  seen  from  the  above  table  that  the  water  content 
of  colostrum  is  less  than  that  of  normal  milk.  The  fat  content 
is  also  a  little  lower.  The  most  striking  characteristics  of  colos- 
trum, however,  are  the  low  content  of  sugar,  and  the  large  amount 
of  albumen.  Of  the  latter  substance  very  little  is  present  in 
normal  milk.  The  mineral  constituents  of  colostrum  also  run 
quite  high.  Its  specific  gravity  varies  from  1.046  to  1.079. 
When  it  is  boiled,  the  nitrogenous  matter  coagulates.  The 
colostrum  is  not  considered  suitable  for  food  until  about  four 
days  after  parturition.  Whenever  it  can  be  boiled  without  coag- 
ulating, it  is  claimed  to  be  safe  to  use.  At  times  a  cow's  udder 
becomes  inflamed  after  calving.  In  such  cases  the  abnormal 
qualities  of  the  cow's  milk  will  extend  over  a  greater^  period  of 
time  than  that  mentioned  above. 

Salty  Milk. — The  average  chemical  analysis  of  salty  milk  as 
calculated  from  results  obtained  by  the  analysis  of  such  milk 
from  four  cows,  given  by  Boggild,1  is  as  follows: 

Water 91 .  09 

Fat 2.09 

Nitrogenous  matter 2 .  90 

Sugar 3.01 

Ash 85 

It  has  an  average  specific  gravity  of  1.0244. 

Salty  milk  does  not  occur  very  often,  but  whenever  it  does 
occur,  it  is  difficult,  and,  so  far  as  known,  impossible  to  cure 
without  drying  up  the  cow.  Two  samples  of  such  milk  have 
recently  come  within  the  authors'  notice.  It  had  the  appearance 
of  normal  milk,  a  foul  smell,  and  a  very  salty  taste.  The  two 
samples  contained  1.7  per  cent  and  1.9  per  cent  of  fat  respectively. 
They  soured  and  curdled  in  a  normal  way  at  living-room  tem- 
perature in  about  thirty  hours.  At  this  stage  they  were  very 
foul  in  smell,  and  unpleasant  in  taste. 

The  cows  which  had  produced  this  milk  had  both  calved 
about  three  months  previously.  It  occurred  in  the  month  of 
July,  when  pastures  were  quite  good.     The  udders  of  the  cows 

1  Maelkeribruget  in  Denmark. 


BLOODY  OR  RED  MILK  67 

were  in  an  apparently  normal  condition.  At  first  it  was  thought 
that  some  conditions  in  the  pasture  caused  this  abnormal  milk. 
The  cows  were  taken  into  the  barn,  and  fed  on  dry  food  for 
two  weeks,  but  without  any  change  in  the  quality  of  the  milk." 
Gradually  they  dried  up. 

The  secretion  of  this  salty  milk  was  believed  to  be  due  to  the 
long  time  during  which  the  cows  had  been  yielding  milk  without 
any  rest.  They  had  been  given  no  rest  previous  to  the  last 
calving.  It  is  also  believed  that  this  quality  of  milk  will  occur 
more  frequently  when  the  cows  are  near  the  close  of  the  lactation 
period. 

While  the  above  two  causes  are  perhaps  the  most  common, 
they  are  not  the  only  ones.  Salty  milk  has  been  obtained  in 
cases  where  these  reasons  could  not  be  ascribed.  Boggild  has 
found  that  salty  milk  has  been  secreted  by  cows  with  abnormal 
udders.  He  has  also  demonstrated  that  it  was  the  diseased  part 
of  the  udder  from  which  the  salty  milk  was  yielded.  The  healthy 
portion  of  the  udder  yielded  normal  milk.  It  is  possible  that 
an  obscure,  diseased  condition  of  the  udder  may  be  the  entire 
cause. 

Salty  milk  is  of  course  undesirable  in  the  dairy  or  creamery. 
It  is  very  disagreeable  to  the  taste,  and  in  a  fermented  stage 
becomes  very  foul. 

Bloody  or  Red  Milk. — Bloody,  or  red  milk  is  caused,  first, 
by  an  abnormal  condition  of  the  cow's  udder,  which  may  or  may 
not  be  apparent;  and  second,  a  red  color  may  be  developed  in 
milk  after  standing,  through  the  action  of  bacteria. 

The  bloody  milk,  caused  by  an  inflamed  udder,  often  assumes 
a  reddish-yellow  appearance,  and  may,  if  not  examined  care- 
fully, be  mistaken  for  colostrum.  Bloody  milk  produced  by  an 
inflamed  udder  may  be  distinguished  by  small  blood  particles, 
which  will  settle  to  the  bottom,  and  can  be  noticed  if  the  sample 
is  placed  in  a  glass  test-tube.  In  bloody  milk  caused  by  bacterial 
growth  the  blood  does  not  show  at  the  bottom,  but  instead, 
previous  to  stirring  the  milk  or  cream,  it  appears  on  the  surface 
in  small  red  dots.  The  red  color  which  commonly  occurs  in  milk 
is  due  chiefly  to  a  species  of  germ  called  Micrococcus  prodigiosus. 


68  ABNORMAL  MILK 

Colostrum  will  show  reddish  cream  on  the  surface,  but  no  blood- 
like material  will  separate  out. 

Blue  Milk. — Blue  milk  is  quite  commonly  found.  Formerly 
it  was  thought  that  this  color  was  due  to  the  condition  of  the 
casein  in  the  milk,  but  since  more  has  been  discovered  in  regard 
to  the  effect  of  germ  life  upon  conditions  and  properties  of  milk, 
it  has  been  proved  that  blue  milk  is  caused  by  bacteria  l  (Bacillus 
cyanogenus).  This  particular  germ  produces  the  blue  color  in 
the  milk  only  when  the  milk  has  an  acid  reaction.  When  sterile 
milk  is  inoculated  with  this  particular  germ,  the  blue  color  is  not 
produced,  but  by  the  addition  of  a  little  acid,  or  by  inoculating 
the  milk  with  the  bacteria  that  produce  lactic  acid,  the  blue  color 
is  produced.  This  seems  to  be  one  of  the  instances  of  symbiotic 
action  of  bacteria  in  milk.  There  are  probably  other  causes, 
but  they  are  not  known.  This  germ,  according  to  Aikman,  is 
killed  by  heating  the  milk  to  about  1760  F.  The  germ  ceases  to 
work  as  soon  as  milk  is  coagulated. 

Yellow  Milk. — According  to  Aikman,1  yellow  milk  is  caused 
chiefly  by  one  species  of  bacteria,  named  Bacillus  synxanthus. 
This  micro-organism  belongs  to  the  group  of  ferments  that  act 
upon  the  fat  of  milk.  There  are  different  shades  of  yellow  pro- 
duced in  milk,  caused  by  different  species  of  bacteria,  but  the 
above-mentioned  one  is  considered  to  be  the  principal  cause. 
Some  produce  a  brilliant  yellow  color,  while  other  species  first 
curdle  the  casein,  and  then  digest  or  dissolve  it  into  a  yellow  or 
amber-colored  liquid. 

Ropy  Milk.  —  Slimy  or  ropy  milk  is  not  common,  but  is 
sometimes  encountered  by  milk-dealers  and  is  caused  by  certain 
micro-organisms.  Aikman  mentions  the  fact  that  no  less  than 
eighteen  different  and  distinct  organisms  have  been  identified  as 
associated  with  this  slimy  fermentation.  Most  of  the  investi- 
gators agree  that  two  organisms  are  chiefly  responsible  for  the 
slimy  condition.  One  of  these  is  Bacillus  lactis  viscosus,2  which 
grows  best  in  the  presence  of  air  and  neither  forms  acid  nor  thrives 
in  an  acid  medium.     This  germ  has  been  found  to  be  frequently 

1  C.  M.  Aikman,  in  "  Milk,  Its  Nature  and  Composition." 

2  Adametz,  Landw.  Jhr.,  1891,  p.  185. 


BITTER   MILK  69 

present  in  surface  waters.  Bouska  broke  off  a  sliver  from  a 
water  tank  which,  when  put  into  milk,  inoculated  it  with  an 
organism  that  produced  ropiness.  The  very  fact  that  milk_ 
dealers  in  cities  are  occasionally  troubled  with  this  sliminess  in 
milk  indicates  that  precautions  are  essential  in  order  to  avoid  the 
presence  of  this  ferment.  The  germ,  when  it  once  gains 
entrance  to  a  milk  establishment,  is  very  difficult  to  eradicate. 
In  order  to  overcome  the  trouble  it  may  be  necessary  to  cover 
the  whole  inside  of  the  milk-store,  and  all  of  the  vessels  used 
for  handling  the  milk,  with  sour  coagulated  milk.  The  lactic 
acid  germs  present  in  this  milk  gain  ascendency  over  the  germs 
causing  sliminess  and  in  that  way  the  trouble  may  be  eradicated. 

Streptococcus  hollandicus  l  is  another  species  which  produces 
sliminess  in  milk.  It  differs  from  the  ferment  mentioned  above 
in  that  it  grows  in  the  absence  of  air  and  produces  acid.  It  is 
used  in  Holland,  in  the  preparation  of  the  slimy  whey  (lange 
Wei)  starter  which  is  added  to  milk  used  in  the  manufacture 
of  Edam  cheese,  just  as  we  use  a  pure  culture  lactic  acid 
starter  in  connection  with  Cheddar  cheese-making. 

Sometimes  milk  is  slimy  when  drawn  from  the  cow — most 
frequently  when  there  is  inflammation  of  the  udder.  There 
are,  in  such  cases,  no  bacteria  present  in  the  milk  as  the  cause 
of  the  ropy  or  slimy  condition.  We  quote  Russell  and  Hast- 
ings: "  The  direct  cause  of  the  abnormal  condition  in  milk  is 
the  presence  of  fibrin  and  white  corpuscles  from  the  blood,  which 
form  masses  of  slimy  material;  in  such  cases  the  trouble  does 
not  increase  in  intensity  with  age,  nor  can  it  be  propagated  by 
transference  to  another  sample  of  fresh  milk." 

Bitter  Milk. — This  is  one  of  the  most  common  kinds  of  abnor- 
mal milk,  and  like  some  of  the  others,  may  have  more  than  one 
cause.  It  may  be  due  to  some  undesirable  food  that  the  cow  has 
eaten,  or  to  the  development  of  certain  germs  in  the  milk.  If 
caused  by  the  food  eaten  by  the  cow,  the  bitter  taste  is  recog- 
nizable immediately  after  the  milk  has  been  drawn.  If  it  develops 
on  letting  the  milk  stand,  it  is  caused  by  bacterial  growth. 

Several  germs  have  been  found  to  be  associated  with  the  pro- 

1  Milch  Zeit.,  1889,  p.  982. 


70 


ABNORMAL   MILK 


MILK  FROM  COWS  WHICH  HAVE  BEEN  IN  MILK  71 

duction  of  this  bitter  flavor  in  milk.  Conn  has  described  a 
micrococcus  which  produces  a  bitter  flavor,  and  Weigmann  has 
described  a  bacillus  which  produces  a  similar  effect.  Nearly 
all  of  the  investigators  agree  that  the  germs  causing  the  bitter 
flavors  in  milk  belong  to  the  group  which  acts  upon  the  casein. 
The  bitter  flavor  is  most  commonly  found  in  milk  that  has  been 
heated  and  then  cooled  to  a  low  temperature.  The  heat  destroys 
the  bacteria  that  produce  lactic  acid,  but  does  not  kill  those  that 
produce  the  bitter  flavor,  owing  to  the  fact  that  they  are  spore- 
producing. 

The  germs  that  produce  a  bitter  flavor  do  not  develop  in 
milk  that  is  partly  soured,  because  an  acid  reaction  is  unfavorable 
to  their  growth. 

It  was  formerly  thought  that  the  organisms  that  cause  the 
bitter  flavor  in  milk  produced  butyric  acid.  This  theory, 
however,  has  been  largely  overthrown,  as  it  has  been  found  that 
these  germs  are  chiefly  of  the  kind  which  peptonize  the  casein 
and  produce  gas. 

Milk  from  Cows  which  Have  Been  in  Milk  for  a  Long  Period.— 
The  difference  in  the  composition  of  the  fat  yielded  by  cows  in 
different  stages  of  the  lactation  period  does  not  seem  to  affect 
the  quality  of  the  milk  to  a  noticeable  extent.  If  the  cows  have 
been  giving  milk  an  unusually  long  time,  the  milk  may  become 
abnormal. 

The  impurities  in  the  small  amount  of  milk  yielded  by  a  cow 
almost  dried  up  are  quite  apparent,  and  the  causes  of  the  presence 
of  these  impurities  are  readily  understood.  The  small  amount  of 
milk  drawn  from  such  a  cow  would  contain  a  proportionately 
larger  amount  of  dirt  and  germs  than  would  a  larger  amount  of 
milk  drawn  from  a  cow  yielding  more  milk,  providing  the  cleanli- 
ness of  the  udder  and  manner  of  milking  were  the  same.  Cows 
giving  a  good  quantity  of  milk  always  seem  to  have  a  cleaner 
udder.  This  has  been  laid  to  the  more  vigorous  circulation  of  the 
blood  in  the  udder  of  the  cow  that  yields  a  larger  portion  of 
milk. 

When  cows  calve  once  a  year,  and  have  a  rest  of  about  seven 
weeks  previous  to  parturition,  if  proper  precautions  are  taken 


72  ABNORMAL  MILK 

concerning  cleanliness,  they  seldom  yield  milk  from  which  a 
first-class  quality  of  butter  cannot  be  produced.  In  practice 
calving  does  not  always  occur  at  regular  intervals.  Several 
instances  have  come  within  the  authors'  notice  where  cows  have 
been  in  milk  for  two  years  or  more  without  coming  in  fresh. 
Such  a  condition  happens  quite  frequently  on  small  farms,  where 
the  cows  kept  are  so  few  that  it  is  deemed  impracticable  to  keep  a 
bull.  As  a  consequence  cows  are  not  served  at  the  proper  time, 
and  great  irregularities  in  calving  are  introduced. 

At  times  it  also  happens  that  cows  become  barren.  In  such 
a  case  they  are  usually  milked  as  long  as  they  will  produce  even  a 
very  small  quantity  of  milk.  Milk  produced  under  such  con- 
ditions is  likely  to  become  abnormal  in  character.*  It  may 
remain  normal  with  a  slight  increase  in  the  fat-content.  The 
abnormal  milk,  so  often  complained  of,  is  usually  the  result 
of  similar  circumstances.  It  is  a  common  belief  that  milk 
yielded  by  such  animals  always  contains  a  high  fat-content,  but 
it  may  contain  very  little  fat,  and  may  be  salty.  It  may  also 
appear  normal,  and  the  cream  when  separated  appear  viscous 
and  dead.  Boggild  states  that  at  the  creamery  the  milk  from 
one  barren  cow  has  more  than  once  produced  difficult  churning. 

Milk  from  Spayed  Cows. — H.  Lennat  has  given  this  kind  of 
milk  considerable  study.  He  finds  that  milk  from  spayed  cows 
may  vary  in  quality  to  the  same  extent  as  milk  from  normal  cows. 
The  solids  of  milk,  as  a  rule,  increase  as  the  spayed  cow  advances 
in  the  milk-giving  period.  This  is  especially  noticeable  in  the 
fat,  sugar,  and  casein.  Such  milk  is  considered  to  be  of  extra 
good  quality,  and  is  recommended  as  being  especially  suitable 
for  infant-feeding. 

Milk  from  Sick  Cows. — Too  much  cannot  be  said  against  the 
use  of  milk  from  sick  cows.  As  soon  as  the  cows  decline  in  health, 
the  quantity  is  noticeably  decreased,  and  the  quality  is  usually 
abnormal.  The  kind  of  milk  yielded  varies  with  different  cows 
and  different  diseases,  but  it  is  interesting  to  note  from  the 
study  of  this  subject,  by  several  men,  that  the  milk-secreting 
glands  are  quickly  affected  by  disease  and  are  unable  to  perform 
their    proper    functions.     Even   a    slight    derangement    of    the 


MILK   FROM   SICK   COWS  73 

digestive  organs  may  have  a  marked  influence  upon  the  flavor 
of  the  milk  and  butter.  When  cows  do  not  clean  well  after 
calving,  the  milk  secreted  by  them  always  has  an  undesirable 
taste.  During  the  time  of  sexual  excitement  of  the  cow,  milk  is 
usually  decreased  in  quantity,  and  in  a  great  many  instances 
possesses  a  very  disagreeable  flavor. 

When  a  cow's  udder  is  inflamed,  the  milk  usually  assumes 
an  abnormal  condition.  It  usually  contains  large,  white  slimy 
lumps.  According  to  Bang,1  this  condition  is  caused  by  a  small 
round  bacterium,  and  is  contagious.  When  this  germ  is  inocu- 
lated into  the  udder,  the  cow  becomes  feverish  and  the  milk  slimy. 

When  cows  become  infected  with  tuberculosis  to  such  an 
extent  that  the  udder  shows  lesions  and  nodules,  the  composi- 
tion and  appearance  of  the  milk  is  altered  considerably.  Milk 
from  such  cows  contains  tubercle  germs,  appears  yellowish- 
brown  in  color,  and  has  an  alkaline  reaction.  The  composition 
of  such  milk  has  been  studied  in  Denmark  and  reported  by 
Boggild  to  be  as  follows: 


Water 88 

Fat 3 

Albuminoids 5 

Sugar i 

Ash 


57 
55 
69 

25 
94 


These  results  represent  the  average  of  four  samples  taken  from 
the  diseased  part  of  the  udder.  It  will  be  seen  that  the  greatest 
variation  from  normal  milk  consists  in  the  small  amount  of  sugar 
it  contains  and  the  high  per  cent  of  ash  and  nitrogenous  matter. 

1  Maelkeribruget  i  Denmark,  by  Boggild. 


CHAPTER  VII 

VARIATION  OF  FAT  IN  MILK  AND  CREAM 

As  the  variations  in  the  per  cent  of  fat  in  milk  and  cream  are 
due  to  such  widely  different  causes,  it  has  been  found  expedient 
to  divide  this  chapter  into  two  parts. 

PART  I 

VARIATION  OF  FAT  IN  MILK 

The  percentage  of  fat  in  normal  milk  varies  a  great  deal 
more  than  that  of  any  of  the  other  constituents.  Dr.  Richmond 
reports  that  the  fat  of  milk  may  go  as  low  as  1.04  per  cent  and 
as  high  as  12.52  per  cent.  Such  extreme  variations  are,  of  course, 
abnormal.  The  fat-content  seldom  falls  below  2§  per  cent  or 
rises  above  7  per  cent.  The  fat-content  of  milk  from  a  whole 
herd  of  cows  varies  only  within  comparatively  narrow  limits. 
The  following  are  the  chief  factors  which  cause  the  fat-content 
of  milk  to  vary : 

(1)  Individuality  of  cows. 

(2)  Breed  of  cows. 

(3)  Time  between  milkings. 

(4)  Manner  of  milking. 

(5)  Whether  the  milk  is  fore  or  after  milk. 

(6)  Age  of  cow. 

(7)  Advance  in  lactation. 

(8)  Feed  of  cows. 

(9)  Environment. 
(10)  Condition  of  cow. 

1.  Individuality. — Whether  a  cow  will  produce  milk  with  a 
high  or  low  fat-content  depends  upon  something  that  is  inherent 
in  the  individual  animal.     Cows  in  the  same  herd,  under  the  same 

74 


VARIATION  OF  FAT  IN  MILK 


75 


conditions  as  to  care,  feeding,  etc.,  will  produce  milk  that  differs 
widely  in  this  respect.  The  secretory  organs  of  the  mammary 
gland  are  the  large  controlling  factor,  and  these  we  cannot 
change.  Even  in  the  same  breed  we  find  animals  that  differ 
very  widely,  as  the  table  below,  compiled  from  complete  records 
by  Eckles,  will  indicate.  These  are  average  yearly  tests  for  the 
highest  and  lowest  testing  animals  in  each  breed. 


Breed 


Jersey. . .  . 
Shorthorn 
Holstein. . 


Number 

Highest 

Lowest 

of 

Per  Cent 

Per  Cent 

Cows 

of   Fat 

of  Fat 

76 

7.00 

4-47 

25 

4-31 

3-59 

40 

3.81 

2.60 

2.  Breed  of  Cows.— The  different  breeds  of  dairy  cattle  have 
their  distinctive  "  breed  characteristics,"  and  the  most  important 
of  these  are  the  quantity  of  milk  they  produce  and  its  richness  in 
butter-fat. 

The  Channel  Island  breeds — Jersey  and  Guernsey — are 
noted  for  the  high  fat-content  of  their  milk;  the  milking  strain 
of  Shorthorns  and  the  Ayrshire  breed  produce  a  milk  of  medium 
richness,  while  the  Holstein  produces  a  milk  somewhat  lower  in 
fat  content.  As  to  quantity  of  milk  produced  the  order  reverses 
itself. 

For  all  the  breeds,  excepting  the  Milking  Shorthorn,  the 
table  which  follows,  giving  the  average  production  and  composi- 
tion of  the  milk  of  the  different  breeds,  is  based  upon  Bulletin  156 
of  the  Bureau  of  Animal  Husbandry  of  the  U.  S.  Department  of 
Agriculture,  which  summarizes  and  digests  the  published  reports 
of  all  the  American  experiment  stations  upon  this  subject. 

3.  Time  between  Milkings. — Where  cows  are  milked  twice  a 
day — the  common  practice  in  the  United  States  and  Canada — 
the  difference  in  the  per  cent  of  fat  in  the  two  milkings  is  quite 
marked,  if  the  intervals  are  very  unequal.  On  the  other  hand,  if 
the  intervals  are  equal,  or  nearly  so,  the  difference  is  not  great. 


76  VARIATION  OF  FAT  IN  MILK  AND  CREAM 

AVERAGE  COMPOSITION  OF  THE  MILK  OF  DIFFERENT  BREEDS 


Breed 


Jersey 

Guernsey 

Ayrshire 

Holstein 

Milking  Shorthorn 


Yearly 

Milk 

Per  Cent 

Pounds 

Yield, 

of  Fat 

of  Fat 

Pounds 

55o8 

5   14 

283 

5509 

4.98 

274 

6533 

3-85 

252 

8699 

3-45 

300 

55oo 

4.00 

220 

Per  Cent 

of  Total 

Solids 


14.9 
14.2 
12.9 
12.3 
13.0 


Experiments  made  by  Ingle  bring  these  points  out  quite  clearly. 
Five  cows  were  milked  at  6  A.M  and  3  p.m.  during  a  period  of 
three  weeks.  The  average  fat-content  of  the  evening's  milk 
was  4.26  per  cent,  while  that  of  the  morning's  milk  was  2.8  per 
cent.  Following  this,  for  four  weeks,  the  cows  were  milked  at 
5.30  a.m.  and  5  p.m.  and  the  average  evening  and  morning  tests 
were  3.80  per  cent  and  3.18  per  cent  respectively.  Even  here 
there  was  a  difference  of  an  hour  in  the  length  of  the  two  inter- 
vals, which  would  account,  largely,  for  the  difference  in  test.  It  is 
claimed,  however,  that  with  equal  intervals  the  evening's  milk  will 
test  slightly  higher  than  the  morning's  milk.  This  is  attributed 
to  greater  activity  of  the  fat-secreting  cells  when  the  cows  them- 
selves are  more  active. 

Milking  three  times  a  day,  as  is  the  custom  in  Denmark, 
increases,  to  some  extent,  both  the  quantity  of  milk  produced 
and  the  per  cent  of  fat  in  it.  But  the  increase  is  not  sufficiently 
marked  to  induce  the  average  farmer  in  America  to  adopt  this 
practice,  except  in  the  case  of  a  cow  which  is  an  exceptionally 
large  producer. 

4.  Manner  of  Milking. — Milking  should  be  done  in  such  a 
manner  as  to  induce  the  cow  to  be  sympathetic  toward  the 
milker.  Hand  milking  should  be  performed  quickly,  but  not 
roughly  or  in  a  way  that  will  excite  the  animal  or  create  discom- 
fort. The  hand  should  close  regularly  and  quickly  from  above 
downward,  in  such  a  way  as  to  extract  the  milk  quickly  and 
efficiently.     The  finger  ends  should  not  press  into  the   teats 


VARIATION  OF  FAT  IN  MILK 


77 


uncomfortably,  nor  should  the  nails  come  into  contact  with  the 
teat  to  the  extent  of  irritating  it.  As  will  be  seen  in  dealing 
with  fore  and  after  milk,  the  milking  must  be  done  thoroughly 
since  the  strippings  are  very  rich  in  fat  content. 

There  is  a  marked  difference  between  milkers.  On  this  point 
we  quote  from  Decker.  "  By  looking  over  the  milking  records 
of  the  University  of  Wisconsin,  it  was  possible  to  pick  out  the 
cows  milked  by  a  certain  milker,  for  he  could  (or  rather  did) 


Fig.  13.— The  wrong  way  to  milk  cows.     (From  Glucose  Sugar  Refining 

Catalogue.) 

invariably  get  more  and  richer  milk  from  the  same  cows  than 
when  the  cows  were  milked  by  other  men." 

5.  Fore  and  After  Milk.— The  first  milk  drawn  from  a  cow  is 
very  low  in  fat  content,  containing  just  a  few  tenths  of  a  per 
cent  of  fat;  while  the  last,  the  strippings,  will  test  very  high, 
often  up  to  8  to  10  per  cent. 

Van  Slyke  of  the  New  York  Station  analyzed  the  different 
portions  of  the  milk  of  a  Guernsey  cow,  with  the  following 
results: 


78 


VARIATION  OF  FAT  IN  MILK  AND  CREAM 


First  portion. . 
Second  portion 
Third  portion . 
Fourth  portion 


Pounds 

1 
Per  Cent 

of  Milk 

of  Fat 

».. 

0.76 

4-i 

2.60 

4.6 

5-35 

5-8 

9.80 

The  practical  lesson  to  be  drawn  from  this  is  that  milking 
should  be  done  efficiently  and  completely. 

6.  Age  of  Cow. — As  already  pointed  out,  the  richness  of  a 
cow's  milk  is  very  largely  determined  by  heredity.  She  will  not 
produce  rich  milk  during  one  lactation  period  and  poor  milk 
during  another.  However,  age  has  its  influence.  Normally 
there  is  a  marked  increase,  from  year  to  year,  in  the  quantity  of 
milk  given,  with  a  tendency  to  a  slight  increase  in  the  fat-content, 
until  a  cow  reaches  maturity.  Then,  in  the  ordinary  course  of 
events,  we  may  look  for  a  gradual  decline.  The  following  is 
quoted  from  Eckles,  whose  investigations  were  both  extensive 
and  thorough :  "  On  the  average,  a  well-grown  two-year-old 
may  be  expected  to  produce  70  per  cent,  a  three-year  old  80 
per  cent  and  a  four-year  old  90  per  cent  of  the  milk  and  fat  that 
she  will  produce  when  mature."  "  The  average  fat-content 
remains  practically  constant  from  year  to  year,  except  that  after 
the  cow  is  eight  or  nine  years  old  the  percentage  of  fat  always 
declines  slowly  and  gradually  with  advancing  years." 

7.  Advance  in  Lactation. — This  is  a  factor  that  materially 
influences  both  the  quantity  of  milk  produced  and  its  fat-content. 
When  a  cow  freshens  she  will  probably,  if  in  reasonably  good 
condition,  produce  milk  with  a  slightly  higher  per  cent  of  fat  in  it 
than  there  will  be  a  little  later.  With  this  exception  the  quan- 
tity of  milk  produced  and  the  per  cent  of  fat  in  it  usually  remain 
fairly  constant  during  the  first  three  or  four  months,  after  which 
there  is  a  gradual  decline  in  the  quantity  of  milk  produced  and  a 
steady  increase  in  its  richness.  But  cows  differ  very  widely  in 
the  rate  of  increase  in  the  fat-content  of  their  milk  as  they 
advance  in  their  lactation  period.     The  following  table  gives  the 


VARIATION  OF   FAT  IN  MILK 


79 


records  of  two  cows  in  the  same  Canadian  herd,  both  of  which 
freshened  in  the  spring  and  at  practically  the  same  time — also 
the  average  for  fourteen  cows  at  the  Geneva  Station : 


Cow  No.  i 

Cow  No.  2 

Geneva 

^14  cows) 

Month 

No. 

Pounds 

Per  Cent 

Pounds 

Per  Cent 

Pounds 

Per  Cent 

of  Milk 

of  Fat 

of  Milk 

of  Fat 

of  Milk 

of  Fat 

i 

546 

3-4 

614 

3-3 

753 

4.02 

2 

618 

3-4 

704 

3 

2 

780 

3 

74 

3 

622 

3-5 

7i4 

3 

7 

7i4 

3 

7i 

4 

723 

3-5 

721 

3 

8 

636 

3 

84 

5 

7i4 

3-7 

693 

4 

1 

588 

3 

87 

6 

636 

3-9 

627 

4 

4 

594 

3 

90 

7 

601 

4.0 

59i 

4 

6 

57o 

3 

94 

8 

54o 

4.1 

502 

5 

1 

480 

3 

89 

9 

427 

4-i 

461 

5 

3 

375 

3 

92 

IO 

214 

4.2 

47 

7 

6 

282 

4 

19 

ii 

168 

4 

58 

8.  Feed  of  Cows. — There  was  at  one  time  a  very  general 
belief,  which  still  has  its  advocates,  that  the  per  cent  of  fat  in 
milk  varies  with  the  nature  of  the  food  the  cow  receives;  but 
many  investigations  made  both  in  America  and  in  Europe  have 
shown  that,  practically  speaking,  the  richness  of  a  cow's  milk  is 
not  influenced  by  her  food.  A  narrow  ration,  one  made  up 
quite  largely  of  concentrates  rich  in  protein,  will  stimulate  the 
milk  flow,  a  fact  which  is  well  known  and  made  use  of  by  those 
experienced  in  the  fitting  and  feeding  of  cows  for  high  official 
records;  but  it  does  not  increase  the  per  cent  of  fat  in  the 
milk. 

Observations  by  the  Copenhagen  (Denmark)  Station  over  a 
period  of  ten  years,  and  including  about  2000  cows,  led  the 
observers  to  conclude  that  foods  high  in  protein  content  may 
possibly  raise  the  fat-content  of  the  milk  to  the  extent  of  0.1 
per  cent — a  very  slight  increase  if  actually  an  increase  at  all. 
Lindsay  of  the  Massachusetts  Station  found  that  a  ration  with  a 


80  VARIATION  OF  FAT  IN  MILK  AND   CREAM 

large  excess  of  protein  stimulated  the  milk  flow  to  the  extent 
of  15  per  cent,  but  he  concluded  that  the  per  cent  of  fat  in  the 
milk  is  not  influenced  by  the  food  a  cow  receives. 

The  addition  of  such  abnormal  foods  as  tallow,  lard,  palm 
and  oleo  oils  to  a  cow's  ration,  or  such  a  radical  change  of  food 
and  environment  as  from  stable  to  pasture  conditions,  may  cause 
a  temporary  change  in  the  per  cent  of  fat  in  a  cow's  milk,  but  the 
change  is  only  temporary. 

9.  Environment. — Such  unfavorable  conditions  as  exposure 
to  inclement  weather,  sudden  changes  in  temperature,  and  poorly 
ventilated  barns  will  cause  a  decrease  in  the  milk  flow.  Experi- 
enced cheese  and  butter-makers  have  noted  a  very  serious  falling 
off  in  the  output  of  their  factories  within  a  comparatively  short 
time,  when  the  cows  were  exposed  to  low  temperatures  and  cold 
storms.  Under  continued  exposure  to  unfavorable  environment 
there  may  be,  at  first,  a  temporary  increase  in  the  per  cent  of  fat 
in  the  milk. 

Reasonable  exercise,  under  suitable  weather  conditions,  is 
favorable  to  both  health  and  a  large  production,  but  excess  of 
exercise  is  not  desirable.  Where  cows  are  confined  to  the  stable, 
without  exercise,  the  production  may  be  quite  satisfactory,  but 
these  conditions  are  detrimental  to  the  health  of  the  animal  and, 
in  the  authors'  opinion,  are  contributory  to  the  spread  of  tuber- 
culosis in  a  herd.  In  Denmark  it  is  the  common  practice  to  keep 
the  cows  closely  confined,  without  exercise,  during  the  winter 
months,  and  tuberculosis  is  very  prevalent  amongst  the  herds  of 
that  country. 

To  secure  the  best  results  we  must  study  the  comfort  of  the 
animal,  and  under  the  head  of  comfort  we  include  favorable 
temperature,  clean  healthful  surroundings  and  the  avoidance  of 
rough  treatment  and  excitement. 

10.  Condition  of  Cow. — If  a  cow  be  in  a  high  state  of  flesh 
when  she  freshens,  her  milk  will  test  much  higher  during  the  first 
few  weeks  than  it  otherwise  would.  Investigations  made  by 
Professor  Eckles  of  Minnesota  University  bring  this  point  out 
very  clearly.  We  submit  the  following  table  based  upon  work 
done  by  him: 


•VARIATION  OF  FAT  IN   CREAM 


81 


Time  after 

No.  207 

No.  217 

No.  300 

Calving 

Days 

Per  Cent 

Per  Cent 

Per  Cent 

2 

5-8 

4-4 

4-5 

5 

4.8 

4.2 

4.2 

IO 

3-9 

3-5 

4.1 

*5 

3-2 

3-7 

3-9 

20 

2-5 

3-4 

3-6 

Months 

3 

2.6 

3-o 

3-6 

6 

2.4 

3-5 

4.0 

9 

3-o 

3-4 

12 

33 

4.1 

Aver,  for  Year 

2.8 

3-4 

3-55 

Compare  the  first  part  of  this  table  with  that  of  the  preceding 
table  in  connection  with  "  Advance  in  Lactation  Period." 

On  the  other  hand,  Eckles  found  that  when  a  cow  begins  to 
put  on  flesh  there  is  the  very  opposite  tendency,  namely,  for  the 
per  cent  of  fat  in  her  milk  to  decline. 


PART  II 


VARIATION  OF  FAT  IN  CREAM 


The  percentage  of  fat  in  cream  delivered  to  creameries  or  for 
city  trade  varies  considerably  from  day  to  day,  and  a  great  deal 
of  dissension  arises  from  the  fact  that  the  producer  does  not  always 
understand  all  the  factors  that  are  responsible  for  this  wide 
variation. 

Extensive  work  has  been  done  by  Professor  O.  F.  Hunziker, 
Purdue  University,  and  similar  work  has  been  carried  on  at  the 
Danish  Experiment  Station  at  Copenhagen.  The  work  done  at 
Purdue  and  other  experiment  stations  plainly  and  conclusively 
shows  that  there  are  a  great  variety  of  factors  and  conditions 
which  control  the  richness  of  cream.  These  factors  influence  the 
richness  of  the  cream  before  it  leaves  the  farm  and  cannot  be 


82  VARIATION  OF  FAT  IN  MILK  AND  *CREAM 

controlled  by  the  creameryman,  who  receives  the  cream  after  it 
has  been  separated.  It  is  physically  impossible  to  produce 
cream  of  exactly  the  same  richness  from  different  skimmings 
under  the  gravity  method  of  creaming.  It  is  impossible  to  so 
operate  the  spoon,  ladle  or  skimmer  as  to  remove  the  same 
amount  of  skim-milk  with  the  cream  each  time.  Where  the 
skim-milk  is  drawn  from  the  bottom  of  the  can  it  is  equally 
impossible  to  so  gage  the  operation  as  to  leave  cream  of  the  same 
richness  in  the  can  at  each  skimming.  Gravity  cream,  or  cream 
obtained  by  gravity  skimming,  is  sure  to  vary  in  richness,  and  it 
is  not  difficult  for  the  producer  to  realize  the  causes  of  variations 
under  this  method  of  creaming.  It  is  more  difficult,  however, 
to  convince  him  that  the  richness  of  the  cream  will  vary  where  the 
small  centrifugal  or  farm  separator  is  used.  The  separator  is  one 
of  the  most  perfect  pieces  of  farm  machinery  in  use,  and  is 
accordingly  expected  to  do  nearly  perfect  work.  It  is  only 
reasonable  that  the  user  of  the  small  centrifugal  machine  will 
expect  to  produce  a  uniform  quality  of  cream;  hence,  when  he 
sells  this  cream  and  finds  that  the  test  is  not  the  same  as  it  was 
on  the  previous  day  he  suspects  that  something  is  wrong.  The 
small  farm  separator  does  produce  the  same  richness  of  cream 
from  different  skimmings,  provided  that  it  is  adjusted  properly, 
that  it  is  operated  in  strict  accordance  with  directions  which 
accompany  it,  and  that  the  richness,  condition  and  temperature 
of  the  milk,  and  the  proportion  of  water  or  skim-milk  used  in 
flushing  the  bowl  to  the  amount  of  milk  separated,  are  the  same. 
The  following  are  the  chief  factors  which  influence  the  per  cent 
of  fat  in  cream: 

(i)  Cream  screw  adjustment. 

(2)  Richness  of  milk. 

(3)  Rate  of  inflow. 

(4)  Speed  of  machine. 
(3)  Temperature  of  milk. 

(6)  Amount  of  water  or  skim-milk  used  to  flush  the  bowl. 

1.  The  Cream  Screw. — The  richness  of  the  cream  obtained 
from  any  farm  separator  is  primarily  determined  and  regulated 


VARIATION  OF  FAT  IN  CREAM  83 

by  the  cream  screw.  The  centrifugal  separator  has  two  main 
outlets,  namely,  the  skim -milk  outlet  located  near  the  periphery 
or  outer  wall  of  the  bowl,  and  the  cream  outlet,  located  near  the 
center  of  the  bowl. 

When  the  milk  enters  the  revolving  bowl  it  is  separated  into 
two  layers,  the  skim-milk  and  the  cream.  The  skim-milk,  being 
heaviest,  is  thrown  against  the  walls  of  the  bowl  where  it  escapes 
through  the  skim-milk  outlet.  The  cream  is  drawn  toward  the 
center  of  the  bowl,  where  it  rises  and  is  discharged  through  the 
cream  screw  or  cream  outlet.  The  cream  screw  is  a  small 
threaded  bolt  with  a  very  minute  opening.  This  bolt  can  be 
turned  so  as  to  move  the  opening  nearer  or  farther  from  the  cen- 
ter of  the  bowl.  When  turned  toward  the  center  it  delivers 
richer  cream,  because  a  smaller  proportion  of  the  milk  is  taken 
as  cream.  When  turned  out  from  the  center  it  delivers  thinner 
cream,  because  a  larger  proportion  of  the  milk  is  taken  as  cream. 

2.  Effect  of  Richness  of  Milk  on  Richness  of  Cream. — The 
richer  the  milk,  the  richer  will  be  the  cream.  With  the  cream 
screw  set  to  deliver  a  certain  and  definite  richness  of  cream  and 
all  other  conditions  normal,  the  separator  will  deliver  a  definite 
ratio  of  skim-milk  and  cream.  This  ratio  varies  according  to  the 
way  the  cream  screw  is  set.  Under  average  conditions  it  may  be 
about  85  to  15;  that  is,  for  each  100  pounds  of  milk  separated 
the  separator  delivers  85  pounds  of  skim-milk  and  15  pounds  of 
cream.  If  all  conditions  are  the  same,  this  ratio  of  skim-milk 
to  cream  remains  constant.  Changes  in  the  richness  of  the  milk 
cannot  alter  the  proportion  of  skim-milk  to  cream  delivered. 
No  matter  how  rich  or  how  poor  the  milk,  each  100  pounds 
of  milk  will  yield  85  pounds  of  skim-milk  and  15  pounds  of 
cream. 

But  because  practically  all  of  the  fat  goes  into  the  cream,  the 
cream  will  contain  more  fat  from  the  separation  of  rich  milk 
than  from  that  of  thin  milk.  This  fact  is  graphically  illustrated 
in  Fig.  14. 

The  illustration  (Fig.  14)  conclusively  shows  that,  all  other 
conditions  being  the  same,  3  per  cent  milk  produces  20  per  cent 
cream,  4.5  per  cent  milk  produces  30  per  cent  cream,  and  6  per 


84 


VARIATION  OF  FAT  IN  MILK  AND  CREAM 


cent  milk  produces  40  per  cent  cream.     Changes  in  the  richness 
of  milk  cause  changes  in  the  richness  of  the  cream.     Any  condi- 


EFFECT  OF  RICHNESS  OF  MILK  UPON  THE  CREAM 


IOO   LBS.    OF   3$  MILK 
CONTAINS   3   LBS.   OF   FAT 


85  LBS. 
SKIM-MILK 


-  30 
"20 


I  5  LBS  -   OF  CREAM  =  3  LBS.  OF  FAT 

TEST    OF    CREAM  =  20$ 
3  , 

-  jx  100  =  20$ 


IOO  LBS.   OF  4.5$  MILK 
CONTAINS  4.5   LBS.   OF   FAT 


15  L3S.  CREAM 
_____ 


85  LBS. 
SKIM-MILK 


15  LBS.  OF  CREAM  =4.5  LBS. OF  FAT 
TEST    OF    CREAM  =  30$ 
7g  x  100  =  30$ 


IOO  LBS.   OF  6$  MILK 
CONTAINS  6    LBS.   OF   FAT 


85  LBS. 

SKIM-MILK 


40$ 


15  LBS. OF  CREAM  =  6  LB*. OF  FAT 
TEST   OF    CREAM  =40$ 
Tr  x  100  =  40$ 


Fig.  14. 

tion,  therefore,  that  affects  the  richness  of  the  milk  will  also  influ- 
ence the  richness  and  the  test  of  the  cream. 

Conditions  that  May  Cause  Changes  in  the  Richness  of  the 
Milk. — During  the  early  summer  months  the  milk  is  usually 
comparatively  low  in  butter-fat.  This  is  caused  by  such  factors 
as  the  freshening  of  the  cows,  change  from  dry  feed  to  succulent 
pasture  and  a  natural  and  inherent  tendency  of  the  cows  toward  a 
decrease  in  the  richness  of  their  milk  in  early  summer.  Toward 
fall  and  early  winter  the  opposite  is  the  case.  The  advanced  state 
of  the  period  of  lactation  and  the  change  from  succulent  to  dry 
feed  cause  the  milk  to  become  richer  in  fat.  It  is  obvious,  there- 
fore, that  in  the  fall  and  winter  the  cream  test  tends  to  be  higher 
than  in  spring  and  early  summer. 

Again,  it  frequently  happens  that  even  in  winter  there  is  a 
sudden  drop  in  the  cream  test.  This  may  be  due  to  the  fact 
that  some  of  the  cows  yielding  rich  milk  dry  up  or  that  some  cows 
come  in  fresh  or  a  new  animal  may  be  brought  into  the  herd. 

The  seasonal  variations  in  the  richness  of  the  cream  may  be 
reduced  by  turning  out  the  cream  screw  a  trifle  in  the  fall  and  by 
turning  it  in  during  the  spring  of  the  year. 


VARIATION  OF  FAT  IN  CREAM 


85 


3.  Effect  of  Rate  of  Inflow   on  Richness    of   Cream. — The 

greater  the  amount  of  milk  passing  through  the  separator  of  a 
definite  capacity  per  hour,  the  thinner  will  be  the  cream.        _    _ 

The  skim-milk  outlet  of  the  bowl  is  constant.  It  can  dis- 
charge so  much  skim-milk  and  no  more.  It  offers  the  first  avail- 
able exit  for  the  milk  in  the  bowl.  Since  it  is  located  at  the 
periphery  of  the  bowl  toward  which  the  skim-milk  is  forced,  it 
discharges  skim-milk. 

All  the  milk  that  flows  into  the  bowl  in  excess  of  what  the 
skim-milk  outlet  can  discharge,  leaves  the  separator  through  the 


EFFECT  OF  RATE  OF  INFLOW  UPON  RICHNESS  OF  CREAM 


NORMAL  INFLOW 

300   LBS.   OF  4$  MILK 
CONTAINS  12   LBS.  OF   FAT 


\— 


45.UBS.   CREAM 


255  LBS. 
SKIM-MILK 


126.7$ 


TEST    OF    CREAM  =26.7$ 
if^x  100  =26.7$ 


LARGE  INFLOW 
350  LBS.  OF  4$  MILK 
CONTAINS  14   LBS.  OF  FAT 


95  LBS.   CREAN 



255  LBS. 
SKIM-MILK 


-20 


TEST   OF   CREAM  =14.7$ 
i|x  100  =14.7$ 


SMALL  INFLOW 

270   LBS.   OF   4$   MILK 
CONTAINS  I0.8  LBS.   OF   FAT 


r.vv 


255  LBS. 
SKIM-MILK 


TEST    OF   CREAM  =72$ 


10.. 


100=72$ 


Fig.  15. 


cream  outlet  or  the  cream  screw.  The  cream  outlet,  being  located 
near  the  center  of  the  bowl  where  the  cream  gathers,  delivers 
cream. 

The  cream  outlet  then  serves  as  the  overflow.  The  greater 
the  amount  of  milk  running  into  the  bowl  in  excess  of  the  capacity 
of  the  skim-milk  outlet,  the  greater  is  the  overflow,  the  more 
milk  will  leave  the  bowl  through  the  cream  outlet  and  the  thinner 
will  be  the  cream.  If  the  separator  is  so  adjusted  that,  under 
normal  conditions,  each  ioo  pounds  of  milk  produces  85  pounds  of 
skim-milk  and  15  pounds  of  cream,  a  300-pound  capacity  machine 


86  VARIATION  OF  FAT  IN  MILK  AND  CREAM 

will  deliver  85X300-M00  or  255  pounds  of  skim-milk  and  the 
remainder,  the  overflow,  will  be  cream.  In  this  case  the  amount 
of  cream  discharged  will  be  45  pounds  (300  —  255=45).  If  the 
separator  is  forced  beyond  its  capacity,  that  is  if  more  than  300 
pounds  of  milk  are  run  into  the  machine,  the  skim-milk  dis- 
charged remains  the  same  and  the  cream  discharged  receives  the 
extra  milk.  Running  350  pounds  of  milk  into  the  machine, 
for  example,  causes  the  separator  to  yield  255  pounds  of  skim- 
milk  and  95  pounds  (350  — 255  =95)  of  cream.  If  the  milk  inflow 
is  reduced  below  the  capacity  of  the  cream,  say  to  270  pounds, 
the  skim-milk  discharged  remains  the  same  (255  pounds)  and 
the  cream  discharged  is  15  pounds  (270—255  =  15).  The  effect 
of  these  variations  in  the  rate  of  inflow  on  the  richness  of  the 
cream  is  shown  in  Fig.  15. 

The  above  diagram  shows  that  almost  any  richness  of  cream 
may  be  obtained  from  the  same  milk  and  the  same  separator 
according  to  the  amount  of  milk  that  flows  into  the  bowl  per  hour. 
A  normal  inflow  produced  26.7  per  cent  cream,  a  large  inflow 
produced  14.7  per  cent  cream  and  a  small  inflow  produced 
72  per  cent  cream. 

Even  the  fullness  of  the  pan  or  tank  from  which  the  milk 
runs  into  the  bowl  affects  the  richness  of  the  cream.  The  fuller 
the  tank  the  more  rapidly  will  the  milk  flow  into  the  bowl  owing 
to  a  few  inches  of  additional  pressure.  If  the  tank  is  kept  filled 
to  the  brim  the  cream  will  be  thinner  than  when  the  tank  remains 
only  one-third  full. 

Every  separator  is  equipped  with  a  simple  device  called  the 
"  Float  "  to  regulate  the  inflow.  The  float  fits  into  the  receiving 
cup  of  the  bowl.  When. too  much  milk  flows  into  the  bowl  the 
float  rises  and  partly  shuts  off  the  outlet  of  the  milk  supply  tank. 
When  too  little  milk  runs  into  the  bowl  the  float  recedes  and  the 
supply  tank  delivers  more  milk. 

The  simplicity  of  the  float  has  had  a  tendency  to  belittle  its 
value  in  the  mind  of  the  average  dairyman,  with  the  result  that 
on  many  farms  it  is  not  used  and  has  been  discarded.  Bearing 
in  mind  the  marked  effect  of  the  rate  of  inflow  on  the  richness  of 
the  cream  it  seems  inconsistent  to  accuse  the  creamery  of  inac- 


VARIATION  OF  FAT  IN  CREAM 


87 


curate  testing  when  the  separator  float  is  a  conspicuous  part  of 
the  scrap  pile  on  the  farm. 

4.  Effect  of  Speed  of  Machine  on  Richness  of  Cream. — The 
speed  of  the  revolving  bowl  produces  the  force — centrifugal  force 
which  drives  the  skim-milk  out  of  the  bowl.  The  greater  the 
speed,  the  greater  the  centrifugal  force  and  the  more  rapidly 
the  skim-milk  leaves  the  bowl.  An  increase  in  the  speed,  there- 
fore, forces  more  skim-milk  through  the  skim-milk  outlet. 
This  means  less  milk  for  the  cream  outlet  and  consequently 


EFFECT  OF  SPEED  UPON  THE  RICHNESS  OF  CREAM 


NORMAL  SPEED 

IOO   LBS.   OF  4.4$  MILK 
CREAM  CONTAINS  44LBS.FAT 


LOW  SPEED 

IOO   LBS.   OF  4.4$  MILK 
CREAM  CONTAINS  2.-1  LBS.FAT 


LBS.   CKEAIV 


90  LBS. 

SKIM-MILK 


i-ifc 


TEST    OF    CREAM 
4gx  100=44$ 


44$ 


HIGH  SPEED 

IOO   LBS.   OF  4.4$  MILK 
CREAM  CONTAINS  4.4  LBS.FAT 


imp 

9  LBS.  CREAM 


81    LBS. 
SKIM-MILK 


19  LBS.  CREAM  CONTAINS 
2.1  LBS.  FAT 

TEST   OF   CREAM  =11$ 
%ix  100  =11$ 


7  LBS.   CREAM 


93  LBS. 
SKIM-MILK 


>63$ 


TEST   OF    CREAM  =63$ 
*!±x  100  =63$ 


Fig.  16. 


richer  cream.  A  decrease  in  the  speed  forces  less  skim-milk 
through  the  skim-milk  outlet,  more  milk  has  to  be  discharged 
through  the  cream  outlet  and  the  cream,  therefore,  is  thinner. 

These  facts  were  established  experimentally.  A  separator 
was  so  adjusted  that,  when  run  at  normal  speed  (60  turns  of 
crank  per  minute),  it  delivered  90  pounds  of  skim-milk  and  10 
pounds  of  cream.  When  the  speed  was  lowered  to  25  turns  of  the 
crank  per  minute,  the  skim-milk  outlet  discharged  only  81  pounds 
of  skim-milk,  increasing  the  amount  of  cream  delivered  to  19 
pounds.  When  the  speed  was  raised  to  75  revolutions  per 
minute,  the  skim-milk  discharge  increased  to  93  pounds,  reducing 


88  VARIATION  OF  FAT  IN  MILK  AND   CREAM 

the  amount  of  cream  to  7  pounds.  The  effect  of  these  variations 
of  speed  on  the  richness  of  the  cream  are  shown  in  Fig.  16. 

Fig.  16  demonstrates  conclusively  that  high  speed  yields  rich 
cream  and  low  speed  yields  thin  cream.  At  normal  speed,  the 
cream  tested  44  per  cent  fat,  at  low  speed  1 1  per  cent  fat,  and  at 
high  speed  63  per  cent  fat.  The  very  low  test  of  cream  from  a 
low  speed  separation  is,  in  part,  due  to  the  fact  that  a  large 
amount  of  fat  (about  one-half  of  the  fat  of  the  milk)  is  lost  in  the 
skim-milk. 

How  to  Run  the  Separator  at  the  Right  Speed. — The  proper 
speed  is  indicated  on  the  crank  of  the  machine.  It  varies  from 
about  40  to  60  turns  of  the  crank  per  minute,  according  to  the 
make  of  the  separator.  If  a  separator  is  to  yield  cream  of  uniform 
richness,  it  must  be  given  the  same  speed  at  each  skimming. 
This  is  possible  only  if  the  operator  times  himself  frequently, 
counting  the  revolutions  of  the  crank  with  watch  in  hand,  or  by 
the  use  of  a  patent  speed  indicator.  The  absence  of  this  pre- 
caution renders  the  work  unreliable.  The  general  tendency  on 
the  part  of  the  operator  is  to  overestimate  the  amount  of  work  he 
puts  into  the  machine;  the  machine  is  run  at  too  low  a  speed. 
Even  the  same  operator  may  vary  the  speed  very  considerably 
at  different  times,  depending  on  his  frame  of  mind  and  physical 
condition.  Again,  where  different  persons  operate  the  machine, 
there  can  be  but  little  uniformity  of  speed,  unless  each  person 
makes  an  effort  frequently  to  count  the  crank  revolutions  by  the 
watch.  The  use  of  a  gasoline  engine  or  some  constant  power 
will  tend  to  give  a  more  uniform  cream  than  when  the  machine  is 
operated  by  hand. 

5.  Effect  of  Temperature  on  Richness  of  Cream. — The  higher 
the  temperature  the  thinner  the  cream.  The  temperature 
influences  the  rate  of  inflow.  The  warmer  the  milk  the  more 
rapidly  will  it  run  from  the  supply  tank  into  the  bowl.  Since 
the  capacity  of  the  skim-milk  outlet  is  fixed,  the  increased  inflow 
of  the  milk  is  discharged  through  the  cream  outlet,  producing  a 
thinner  cream.  Experimental  results  showed  that  when  the 
separator  was  so  adjusted  as  to  yield  15  pounds  of  cream  and 
85  pounds  of  skim-milk  from  every  100  pounds  of  milk  separated 


VARIATION  OF  FAT  IN  MILK  AND  CREAM 


89 


at  900  F.,  a  drop  in  the  temperature  to  500  F.,  caused  the 
amount  of  cream  delivered  to  decrease  to  5.5  pounds  and  the 
skim-milk  to  increase  to  94.5  pounds.  These  results  are  graph- 
ically illustrated  in  Fig.  17. 

The  results  expressed  in  Fig.  17  show  that  when  the  tempera- 
ture of  the  milk  is  decreased  below  normal,  the  richness  of  the 
cream  increases.  At  900  F.,  the  cream  contained  26  per  cent  fat. 
At  500  F.  it  contained  40  per  cent  fat.  The  increase  in  the  test 
of  the  cream  from  the  cold  milk  would  be  still  greater,  if  it  were 


— — ^— '    ' 

EFFECT  OF  TEMPERATURE  UPON  RICHNESS  OF  CREAM 

TEMPERATURE  OF  MILK  90-95° F. 

TEMPERATURE  OF  MILK  50°F. 

lOO   LBS.   OF  3.9.*  MILK 

lOO  LBS.  OF  3.9#  MILK 

CREAM    CONTAINS  3.9  LBS.   FAT 

CREAM   CONTAINS  2.2  LBS.    FAT 

lb  LBS.   CREAM 

; 

50 

5.5  LBS. CREAM 

50 

85  LBS. 
SKIM-MILK 

1 

30 

94.5  LBS. 
SKIM-MILK 

y 

15  LBS.  CREAM  CONTAINS  3.9  LBS.  FAT 

5.5  LBS.  CREAM  CONTAINS  2.2  LBS.  FAT 

TEST   OK   CREAM  =  26# 

TEST   OF   CREAM  =  40# 

ff  x  100=26# 

f|x100=40# 

Fig.  17. 

not  for  the  fact  that  at  that  temperature  a  large  amount  of  fat 
is  lost  in  the  skim-milk. 

The  Proper  Temperature  for  Separation. — The  best  practical 
temperature  at  which  to  separate  the  milk  on  the  farm  is  about 
900  F.  The  milk  is  never  in  better  condition  for  separation  than 
immediately  after  it  is  drawn.  It  then  has  a  temperature  of 
about  900  F.  to  950  F.  If  the  milk  is  allowed  to  cool  to  a  much 
lower  temperature,  as  is  the  case  in  the  winter,  when  the  separator 
is  operated  only  once  per  day,  or  once  in  several  days,  it  should  be 
warmed  up  to  about  900  F.  before  it  is  run  through  the  separator; 
otherwise  there  is  bound  to  be  a  considerable  variation  in  the 
cream  test  and  also  an  increased  loss  of  fat  in  the  skim-milk. 


90  VARIATION  OF  FAT  IN  MILK  AND   CREAM 

6.  Effect  of  Amount  of  Water  or  Skim-milk  Used  to  Flush  the 
Bowl. — The  more  water  or  skim-milk  used  to  flush  the  bowl,  the 
thinner  will  be  the  cream. 

At  the  conclusion  of  the  separation  there  remains  in  the  bowl 
and  in  the  cream-discharging  pan  a  considerable  quantity  of 
cream.  In  order  to  save  this  cream  it  is  necessary  to  flush  the 
bowl  with  water  or  with  skim-milk.  If  enough  water  or  skim- 
milk  is  used  the  cream  remaining  in  the  separator  is  flushed  out 
and  discharged  into  the  cream  can. 

The  extent  to  which  the  cream  test  is  lowered  by  flushing  the 
bowl  will  depend  on  the  amount  of  water  or  skim-milk  used,  the 
manner  in  which  it  is  added  and  the  amount  of  milk  separated. 

If  just  enough  water  or  skim-milk  is  used  to  thoroughly  rinse 
out  the  bowl  and  the  pan  or  tank,  the  richness  of  the  cream  is 
not  materially  changed.  An  excess  of  water  or  skim-milk  may 
cause  a  considerable  decrease  in  the  richness  of  the  cream. 

If  the  water  or  the  skim-milk  is  poured  into  the  supply  tank 
and  is  allowed  to  run  into  the  machine  gradually,  most  of  it  will 
escape  through  the  skim-milk  outlet  and  the  richness  of  the  cream 
will  be  changed  but  very  little.  If  the  water  or  skim-milk  is 
poured  directly  into  the  receiving  cup  of  the  bowl,  with  the  float 
discarded,  it  will  run  into  the  bowl  much  more  rapidly  and  more 
of  it  will  get  into  the  cream. 

The  smaller  the  amount  of  milk  used  for  the  separation,  the 
more  the  cream  is  thinned  down  by  the  flushing. 

Experimental  data  show  that  the  cream  test  may  be  lowered 
from  i  to  10  per  cent  according  to  the  amount  and  conditions  of 
the  flushing.  Enough  water  or  skim-milk  has  been  used  when 
the  cream  discharge  begins  to  appear  watery.  Hot  water  or 
warm  milk  will  drive  the  cream  out  of  the  bowl  more  quickly  and 
may  produce  a  higher  testing  cream. 

The  Proper  Richness  of  the  Cream. — Too  thin  cream  is  not 
satisfactory  because  it  leaves  but  a  small  amount  of  skim-milk 
for  the  use  of  the  dairy  farmer,  it  increases  the  cost  of  transpor- 
tation, it  sours  and  spoils  more  rapidly,  it  prohibits  the  use  of  a 
reasonable  amount  of  starter  for  ripening  at  the  creamery,  it 
does  not  churn  out  exhaustively,  and  yields  an  excessive  amount 


VARIATION  OF  FAT  IN  CREAM  91 

of  buttermilk,  augmenting  the  loss  of  fat  and  therefore  reducing 
the  churn  yield. 

Too  thick  cream  is  undesirable  because  it  may  cause  the~sep- 
arator  to  clog,  it  increases  the  loss  in  handling,  it  is  difficult 
to  properly  sample  and  interferes  with  the  accuracy  of  the  test. 

The  most  satisfactory  cream  for  butter-making  is  that  which 
tests  about  30  to  4c  per  cent  fat.  It  is  desirable  to  produce 
somewhat  richer  cream  in  summer  than  in  winter  to  prevent 
excessive  souring  in  summer  and  difficult  handling  in  winter. 

Effect  of  These  Factors  upon  the  Skimming  Efficiency  of  the 
Separator. — The  richness  of  the  milk  has  no  effect  on  the  com- 
pleteness of  the  skimming. 

The  richness  of  the  cream,  within  reasonable  limits,  has  no 
effect  on  the  completeness  of  the  skimming.  The  skimming  of 
very  rich  cream  causes  a  large  loss  of  fat  in  the  skim-milk  in  the 
case  of  certain  makes  of  separators,  due  to  the  clogging  of  the 
machine. 

The  Rate  of  Inflow  Greatly  Affects  the  Completeness  of  the 
Skimming. — If  more  milk  is  run  into  the  machine  than  the  capac- 
ity of  the  machine  calls  for,  there  is  excessive  loss  of  fat  in  the 
skim-milk.  If  the  rate  of  inflow  is  reduced  below  the  capacity  of 
the  skim-milk  outlet,  the  separator  delivers  no  cream  at  all. 

The  Speed  of  the  Separator  Greatly  Influences  its  Skimming 
Efficiency. — Excessive  speed  does  not  increase  the  completeness 
of  the  skimming.  Insufficient  speed  increases  the  loss  of  fat  in 
the  skim-milk.  A  separator  run  at  half  speed  may  cause  one-half 
of  the  fat  of  the  milk  to  be  lost  in  the  skim-milk. 

The  Temperature  of  the  Milk  Affects  the  Skimming  Efficiency 
of  the  Separator.— For  all  practical  purposes  a  temperature  of 
900  F.  causes  efficient  skimming.  At  lower  temperatures  there  is 
excessive  loss  of  fat  in  the  skim-milk. 

The  Amount  of  Water  or  Skim-milk  used  to  Flush  the  Bowl 
Regulates  the  Amount  of  Fat  Lost  in  the  Bowl  and  Pan. — If  the 
bowl  is  not  flushed  at  all,  or  insufficiently,  varying  amounts  of 
fat  may  be  lost.  If  the  bowl  is  flushed  until  the  cream  discharge  is 
watery,  most  of  the  fat  in  the  bowl  and  pan  is  recovered  and 
saved. 


CHAPTER  VIII 

RECEIVING,  SAMPLING,  GRADING  AND  TESTING  MILK 

AND  CREAM 

Receiving  and  Grading  of  Milk  and  Cream. — The  man  who 
receives  and  samples  milk  at  a  creamery  should  be  accurate  and 
quick  at  figures,  have  ability  to  grade  and  select  milk,  and  to 
stimulate  interest  in  the  production  of  good  milk.  He  should 
also  be  able  to  reconcile  and  satisfy  patrons.  The  method 
employed  in  some  creameries  of  allowing  a  boy  with  immature 
judgment  to  weigh  and  sample  milk  should  not  be  tolerated. 
The  person  who  weighs  and  samples  milk  and  cream  comes  in 
direct  contact  with  the  patrons.  Therefore,  he  is  a  strong  factor 
in  serving  the  best  interests  of  the  creamery.  In  many  of  the 
best  butter  and  cheese  factories  in  the  country  the  head  maker 
or  manager  in  charge  is  usually  found  at  the  weighing  can.  This 
gives  him  the  opportunity  of  studying  the  raw  material  from  which 
he  is  expected  to  make  a  high  grade  of  butter  or  cheese.  Some 
of  our  large  central  plants  pay  the  highest  salary  to  the  man  who 
has  the  ability  properly  to  grade  the  cream  and  prepare  the 
starters.  This  requires  a  fine  sense  of  smell  and  taste,  which  is 
not  possessed  by  everyone. 

The  first  step  in  the  receiving  of  milk  is  to  ascertain  the  quality 
of  the  milk  delivered  by  the  patrons.  It  is  now  a  recognized 
fact  that  the  best  butter  cannot  be  produced  from  defective  or 
abnormal  milk  or  cream,  no  matter  how  many  improved  methods 
are  employed  in  the  manufacture.  In  view  of  this  fact,  and  of 
the  knowledge  we  now  have  of  the  transmission  of  undesirable 
germs  from  one  sample  of  milk  to  another,  and  also  the  probability 
that  some  of  the  patrons  will  deliver  poor  milk,  it  is  essential  that 
the  milk  or  cream  be  graded  when  it  is  delivered  at  the  creamery. 

92 


RECEIVING    AND    GRADING    OF    MILK    AND    CREAM       93 

In  the  grading  of  milk  or  cream,  different  methods  can  be 
used  for  detecting  abnormal  milk:  (i)  through  the  senses, 
taste,  sight,  and  smell;  (2)  by  the  acid  tests;  (3)  by  the  fermenta- 
tion test;  (4)  by  heating;  (5)  by  the  Babcock  test  and  the  lac- 
tometer. 

While  all  of  these  tests  are  applicable  to  the  grading  of  milk, 
only  the  first  and  a  portion  of  the  fifth  are  usually  applied  to 
cream. 

1.  Detection  of  Abnormal  Milk  and  Cream  through  the 
Senses. — In  order  to  detect  the  different  kinds  of  defective- milk 
one  must  be  endowed  with  acute  senses  of  smell,  taste,  and  sight. 
When  the  milk  is  in  a  good  condition,  it  has  a  pleasant  smell  and 
sweet  taste,  and  appears  normal.  This  applies  equally  to  cream 
with  the  exception  that  not  all  cream  for  butter-making  is  sweet. 
If  milk  has  a  disagreeable  smell  and  taste  it  cannot  produce  good 
butter.  As  a  rule,  the  quantity  of  defective  milk  brought  into 
the  average  creamery  is  much  in  excess  of  that  of  really  perfect 
milk.  As  a  consequence  it  would  not  be  practicable  to  separate 
all  the  defective  milk  into  one  class  and  the  perfect  into  another. 
The  question  as  to  where  the  line  should  be  drawn  between  the 
good,  medium,  and  very  bad  milk  or  cream,  must  depend 
upon  the  judgment  of  the  receiver,  and  in  a  great  measure  upon 
the  local  conditions.  Some  of  the  creameries  have  no  facilities 
for  handling  different  grades  of  milk,  and  some  sell  butter  on  a 
market  where  no  sharp  distinction  is  made  between  good  and 
poor  butter.  Others  have,  through  experience,  satisfied  them- 
selves that  under  American  creamery  conditions  it  does  not  pay 
to  make  too  many  grades,  nor  does  it  pay  to  grade  too  closely. 
Two,  or  at  the  most  three,  grades  of  butter  can  at  times  be  man- 
ufactured in  one  creamery  profitably.  It  is  advisable  to  reject 
sour  and  abnormal  milk.  If  accepted,  it  should  not  be  mixed 
with  the  remainder  of  the  milk,  as  it  might  contaminate  all  of  it; 
or,  the  sour  milk  might  cause  coagulation,  and  thereby  clog  up 
the  separators.  If  a  can  of  milk  is  sour,  but  otherwise  clean,  it  is 
not  necessarily  unfit  for  the  production  of  first-class  butter.  If 
retained  until  after  the  sweet  milk  has  been  skimmed,  it  may  be 
run  through  the  separator  successfully. 


94  GRADING  AND  TESTING  MILK  AND   CREAM 

2.  The  Use  of  Acid  Tests. — Some  creameries  are  now  grading 
the  milk  or  cream  according  to  the  amount  of  acid  it  contains. 
Mann's  and  Farrington's  acid  tests  can  both  be  used,  but  a  more 
rapid  and  convenient  way  is  to  use  a  solution  prepared  from  Far- 
rington's tablets.  The  solution  is  prepared  by  dissolving  the 
tablet  in  warm  water,  using  an  ounce  of  water  to  a  tablet.  When 
one  part  of  this  alkaline  solution  and  one  part  of  milk  are  mixed 
together  in  a  cup  and  the  solution  still  retains  a  pink  color,  it  shows 
that  there  is  less  than  .1  per  cent  acid  in  the  sample  tested.  If 
two  parts  of  alkali  and  one  part  of  milk  are  mixed  and  the  mixture 
remains  pink,  then  there  is  less  than  .2  per  cent  of  acid.  If  the 
mixture  becomes  colorless,  it  shows  there  is  more  than  .2  per  cent 
acid  in  the  sample.  If  three  measures  of  alkali  to  one  rneasure 
of  milk  are  taken,  and  the  mixture  remains  pink,  there  is  less 
than  .3  per  cent  of  acid,  etc.  By  means  of  such  a  test  the  acidity 
can  quickly  be  determined. 

The  sample  cups  should  be  numbered  to  correspond  with  the 
number  of  each  patron.  The  results  of  the  tests  should  be 
noticed  at  once,  as  the  action  of  the  atmosphere  affects  the  color. 

The  acid  tests  are  of  value  in  grading  cream,  as  a  sour  sample 
of  milk  or  cream  is  either  old  or  has  been  improperly  kept  and 
handled.  The  number  of  grades  of  cream  and  milk  and  the  max- 
imum limit  of  acid  each  grade  can  contain,  are  factors  which 
must  be  decided  according  to  local  conditions,  by  the  operator. 

3.  Use  of  the  Fermentation  Tests. — Curdled,  ropy,  red  and 
blue  milk  can,  as  a  rule,  be  readily  detected  without  the  appli- 
cation of  a  special  test,  but  there  are  cases  when  a  person's 
senses  are  not  sufficiently  acute  to  detect  samples  of  milk  con- 
taining undesirable  fermentations.  Several  instances  have 
recently  come  within  the  authors'  notice.  A  neighboring  cream- 
ery was  infested  with  a  peculiar  fermentation  that  caused  a  very 
rank  flavor  in  the  butter.  The  milk  that  came  to  the  creamery 
was  carefully  examined,  but  the  source  of  the  trouble  could  not 
be  located.  The  cause  could  not  be  ascertained  without  the  use 
of  the  fermentation  test. 

It  is  in  such  instances  that  a  fermentation  test  is  of  special 
value.     As  a  rule,  the  trouble  is  first  caused  by  milk  from  one 


RECEIVING    AND     GRADING    OF    MILK    AND     CREAM       95 

particular  patron.  This  milk  may  appear  to  be  normal,  and  yet 
contain  germs  which  are  very  undesirable  for  the  manufacture  of 
the  best  quality  of  butter. 

Fermentation  Tests. — There  are  two  tests  which  may  be  of 
general  use;  namely,  the  "  Wisconsin  Curd  Test"  and  the 
"  Gerber  Fermentation  Test."  The  former  is  used  in  cheese 
factories,  but  the  latter  is  to  be  recommended  in  testing  milk  for 
butter-making. 

Gerber  Test. — The  apparatus  for  this  test  consists  of  properly 
made  glass  tubes  resting  upon  a  rack  which  fits  into  a  small 
round  tin  tank,  about  two-thirds  full  of  water.  The  temperature 
of  this  water  can  be  controlled  by  means  of  a  lamp  kept  burning 
underneath,  or  by  the  use  of  steam.  The  milk  delivered  by  dif- 
ferent patrons  is  put  into  the  glass  tubes,  and  these  are  numbered 
so  as  to  indicate  to  which  patron  each  belongs.  The  tempera- 
ture should  be  kept  at  about  1040  to  1060  F.  for  about  six  hours. 
Then  the  tubes  are  taken  out,  the  milk  shaken,  and  the  appear- 
ance, smell,  and  taste  of  the  milk  noted.  The  tubes  are  warmed 
again  for  about  another  six  hours,  when  they  are  again  examined. 
If  any  samples  contain  a  preponderance  of  abnormal  ferments, 
the  fact  will  usually  appear  in  less  than  eighteen  hours.  If 
milk  does  not  coagulate  in  twelve  hours,  or  become  abnormal 
in  some  way,  it  is  considered  good. 

The  special  apparatus  mentioned  above  is  not  absolutely 
essential,  nor  is  the  temperature  employed  considered  by  the 
authors  to  be  the  most  suitable  to  give  reliable  results.  Ordinary 
sample  jars  can  be  used,  instead  of  specially  prepared  tubes. 
After  the  milk  has  been  placed  in  the  jars  they  can  be  kept  in  any 
convenient  place,  at  a  temperature  of  about  980  F.  The  best 
place  to  keep  them  is  in  a  vessel  containing  water,  the  temperature 
of  which  can  be  controlled. 

Wisconsin  Curd  Test. — This  test  consists  of  taking  some  milk 
in  a  jar  and  adding  about  ten  drops  of  rennet,  which  coagulates 
the  milk.  The  sample  is  allowed  to  stand  until  the  curd  hardens, 
when  it  is  cut  into  small  pieces  with  a  case  knife;  the  whey  is 
drawn  off,  and  the  curd  allowed  to  stand  at  a  temperature  of 
98 °  F.     If  there  are  any  undesirable  forms  of  bacteria  present, 


96 


GRADING  AND   TESTING   MILK   AND    CREAM 


they  will  reveal  themselves  by  developing  small  holes  in  the  curd, 
usually  accompanied  by  a  bad  odor. 

This  test  is  a  very  ingenious  one  for  cheese-making.  In 
butter-making  the  Gerber  Fermentation  Test,  or  a  similar  one, 
is  more  convenient. 

4.  Grading  Milk  by  Heating. — This  test  is  not  very  much 


Fig.  18. — Troemner's  Babcock  cream- testing  scales. 

used  in  creameries ;  but  in  cheese  factories  the  heating  of  milk  in 
order  to  ascertain  its  suitability  for  cheese-making  is  practiced 
to  a  considerable  extent.  The  heating  test,  which  is  in  common 
use  in  Canada,  consists  of  heating  a  small  sample  of  the  milk  to  be 
tested  to  1200  F.  If  it  will  stand  this  temperature  without  coag- 
ulating, it  is  considered  to  be  good  milk.  If  it  coagulates  when 
heated  to  this  temperature,  it  is  too  sour 
to  be  used  for  cheese. 

This  heating  may  be  considered  an 
acid  test.  When  milk  contains  about 
.3  per  cent  acid,  it  usually  coagulates 
when  heated.  It  should  be  borne  in 
mind  in  this  connection  that  different 
samples  of  milk,  containing  exactly  the 
same  amount  of  acid,  do  not  coagulate  at  the  same  tempera- 
ture. Some  samples  will  coagulate  upon  heating  when  contain- 
ing a  little  less  than  .3  per  cent  acid,  while  others  will  not 
coagulate  until  more  than  .3  per  cent  acid  has  developed. 

In  practice  the  temperature  (1200  F.)  is  not  always  closely 


Fig.    19. — Troemner's    Bab 
cock  cream-testing  scales. 


RECEIVING    AND     GRADING    OF    MILK    AND     CREAM       97 

adhered  to.     A  small  portion  of  the  sample  to  be  tested  is  put 
into  a  tin  cup,  and  the  cup  is  put  into  hot  water  or  over  a  jet  of 

steam.     When  the  milk  is  hot  its  characteristics  are  noticed. 

5.  Use  of  Babcock  Test  and  Lactometer. — These  tests  are 
of  special  value  in  detecting  watered  or  skimmed  milk.  When- 
ever a  sample  of  milk  appears  watery  or  blue,  it  is  fair  to  presume 
that  water  has  been  added.  The  test  for  specific  gravity  and  the 
test  for  fat  can  then  be  applied  to  such  samples  of  milk.  As  a  rule 
composite  samples  are  taken  daily  at  creameries,,  and  the  patrons 


Fig.  20. — Acid  carboy  trunnion. 


Fig.  21. — Acid  hydrometer. 


paid  according  to  the  fat  delivered.  For  this  reason  water  adul- 
teration is  not  very  common  at  creameries,  but  is  practiced  to  a 
greater  extent  in  the  milk-supplies  of  cities.  The  use  of  the  lac- 
tometer in  connection  with  the  Babcock  test  has  already  been 
referred  to  under  the  heading  of  "  Specific  Gravity  of  Milk." 

The  Babcock  test  is  now  in  such  general  use  in  America  for 
determining  the  per  cent  of  fat  in  milk  and  cream  that  no  other 
will  be  dealt  with  here.  At  one  time  the  Oil-test  Churn  was  used 
quite  exclusively  for  testing  cream,  but  it  has  gone  almost  entirely 
out  of  use. 


98  GRADING  AND  TESTING   MILK   AND   CREAM 

The  Babcock  test  always  deals  with  weight.  For  instance, 
when  we  say  that  a  sample  of  milk  tests  4.0  per  cen't  or  that  a 
sample  of  cream  tests  30.0  per  cent,  we  mean  that  in  100  pounds 
of  the  milk  there  are  4  pounds  of  fat,  or  in  100  pounds  of  the 
cream  there  are  30  pounds  of  fat. 

For  the  sake  of  convenience  a  sample  may  be  measured  into  a 
test  bottle  instead  of  being  weighed,  when  the  accuracy  of  the 
result  is  not  likely  to  be  affected.  Milk  may  be  sampled  for  the 
Babcock  test  with  a  pipette,  because  the  specific  gravity  of  milk  is 
always  so  nearly  the  same  that  the  same  measure  of  milk  from 
widely  different  sources  has,  for  all  practical  purposes,  the  same 
weight,  and  because  milk  is  in  such  a  liquid  condition  that  it 
neither  holds  air  nor  adheres  to  the  wall  of  the  pipette^  Rich 
cream,  on  the  other  hand,  has  a  lower  specific  gravity  than  thin 
cream;  moreover,  cream  is  so  syrupy  or  viscous  in  its  nature  that 
it  will  hold  air  or  other  gas  and  stick  to  the  wall  of  the  pipette. 
For  these  different  reasons,  the  authors  wish  to  state  emphat- 
ically, that  when  cream  is  tested  for  commercial  purposes,  as  at  a 
creamery,  it  should  never  be  measured  but  always  weighed  into 
the  test  bottle.  The  measuring  of  cream  for  the  Babcock  test, 
when  this  test  is  made  for  commercial  purposes,  is  a  fraudulent 
practice;  and  in  most  of  the  States  and  Provinces  of  the  United 
States  and  Canada  there  are  laws  prohibiting  it. 

In  taking  the  sample  for  a  Babcock  test  of  milk  a  17.6  c.c. 
pipette  is  used.  This  will  deliver  18  grams  of  milk,  the  quantity 
for  which  the  scale  on  the  test  bottle  is  graduated  to  read  per 
cent  of  fat.  To  this  we  add  17.5  c.c.  of  sulphuric  acid  (specific 
gravity  1. 82-1 .83),  varying  the  quantity  to  suit  the  strength. 
The  contents  are  then  thoroughly  mixed  by  giving  the  bottle  a 
rotary  motion.  The  acid  acts  upon  and  digests  all  the  solids  of 
the  milk,  excepting  the  fat,  and  heats  the  sample  to  a  desirable 
high  temperature.  The  bottle  is  then  placed  in  the  centrifugal 
tester  and  whirled  for  five  to  six  minutes,  at  a  speed  suitable 
to  the  diameter  of  the  machine,  usually  800  to  1000  revolutions 
per  minute.  The  bottle  is  then  filled  to  the  bottom  of  the  neck 
with  hot  water  (soft  or  distilled)  and  whirled  for  about  two  min- 
utes.    A  second  addition  of  hot  water  is  then  made  to  float  the 


RECEIVING    AND     GRADING    OF    MILK    AND     CREAM       99 

fat  into  the  neck  to  about  the  8  per  cent  mark,  after  which  the 
sample  is  given  a  final  whirling  of  one  minute.  The  sample  is 
then  set  in  hot  water  at  i30°-i40°  F.  to  bring  it  to  the  right_tem- 
perature  for  reading.  A  pair  of  dividers  is  generally  used  for 
measuring  the  fat  column  in  taking  the  reading.  With  milk, 
the  reading  is  taken  from  the  highest  to  the  lowest  point,  that  is, 
the  meniscus  of  the  fat  column  is  included. 


Fig.  22.  Fig.  23.  Fig.  24.  Fig.  25. 

Skim-milk  Whole-milk  Cream  test-        •  9-gram  cream 

test-bottle.  test-bottle.  bottle.  test-bottle 

Babcock  Test-bottles. 


3o 


Fig.  26. 
Cream 
test-bottle 


In  the  Babcock  test  of  cream  either  a  9-  or  an  18-gram  bottle 
is  used.  The  drift  has  been  decidedly  towards  the  use  of  the 
bottle  graduated  to  read  per  cent  for  9  grams.  A  9-gram  sample 
of  cream  is  weighed  into  the  bottle  by  means  of  a  special  cream 
scale.  To  this  are  added  about  9  c.c.  of  commercial  sulphuric 
acid,  and  the  contents  are  mixed  by  giving  the  bottle  a  rotary 
motion.     When  the  action  of  the  acid  has  proceeded  far  enough — 


100  GRADING  AND   TESTING  MILK   AND   CREAM 

when  the  contents  have  reached  a  chocolate  color — some  hot 
water  is  added  to  the  test  bottle  to  check  the  action  of  the  acid. 
The  sample  is  then  centrifuged  for  five  to  six  minutes,  after  which 
hot  water  is  added  to  float  the  fat  into  the  neck  of  the  bottle; 
then  the  sample  is  again  whirled  for  two  minutes.  The  reading 
is  taken  at  a  temperature  of  i3o°-i4o°  F.,  after  a  few  drops  of  a 
colored  reader,  composed  of  a  light  mineral  oil  with  suitable 
coloring  matter  in  it,  have  been  added  to  flatten  the  meniscus. 
Dividers  are  used  for  measuring  the  fat  column  in  taking  the 
reading. 

There  are  three  very  common  conditions  which  make  it  dif- 
ficult to  obtain  a  fat  reading:  (i)  Black,  charred,  flocculent 
matter  is  sometimes  found  at  the  bottom  of  the  fat  column.  This 
is  commonly  caused  by  using  too  much  or  too  strong  acid  or  by 
mixing  milk  and  acid  at  too  high  a  temperature.  The  remedy 
is  to  use  less  acid  or  to  cool  milk  and  acid  before  mixing.  The 
black  charred  matter  may  also  be  due  to  allowing  the  acid  to 
stand  in  contact  with  the  milk  too  long  a  time  before  mixing  or  to 
pouring  acid  through  the  center  of  the  milk.  (2)  There  may  be  a 
layer  of  white  flocculent' matter  at  the  bottom  of  the  fat  column. 
In  this  case  an  insufficient  quantity  of  acid  may  have  been  used, 
the  temperature  of  the  milk  and  acid  may  be  too  low,  or  they 
may  not  have  been  thoroughly  mixed.  The  remedy  is  to  use 
more  acid,  to  warm  milk  and  acid  before  mixing,  or  to  shake  the 
mixture  thoroughly  before  whirling.  (3)  Occasionally  there  is  a 
layer  of  impure  foam  at  the  top  of  the  fat  column.  This  is  gen- 
erally due  to  the  use  of  hard  and  impure  water.  The  remedy  is  to 
use  pure  distilled  hot  water.  For  more  detailed  information  on 
this  subject  see  "  Testing  Milk  and  its  Products,"  by  Farrington 
and  Woll. 

Does  the  Babcock  Test,  as  Ordinarily  Applied  to  Cream,  Give 
too  High  a  Reading? — An  investigation  made  by  Harry  B.  Sieg- 
mund,  Analyst,  Hendler  Creamery  Company,  and  R.  Sewell 
Craig,  Senior  Food  Chemist,  City  Health  Department,  Balti- 
more, resulted  in  a  decision  that  the  Babcock  test  of  cream,  as 
ordinarily  conducted,  gives  too  high  a  reading.  The  following  is 
a  brief  summary  of  the  results  obtained : 


BABCOCK  TEST  OF  BUTTERMILK  AND  SKIM-MILK        101 

When  the  centrifuging  was  done  in  a  thirty-six  bottle,  elec- 
trically driven  machine,  run  at  a  speed  of  iooo  revolutions  per 
minute,  the  average  of  the  tests  of  a  number  of  samples  of  cream 
was  i  .o  per  cent  higher  than  that  obtained  by  gravimetric  analy- 
sis (Rose- Gottlieb  test);  and  where  the  test  was  made  with  a 
twenty-four  bottle  steam-turbine  machine,  run  at  a  speed  of  800 
revolutions  per  minute,  the  average  test  was  1.5  per  cent  too 
high. 

With  the  electrically  driven  machine  run  at  a  speed  of  1200 
revolutions  per  minute  the  reading  was  0.6  per  cent  higher  than 
that  obtained  by  the  Rose- Gottlieb  test. 

When  an  electrically  driven  machine,  run  at  a  speed  of  1600 
revolutions  per  minute,  was  used,  the  Babcock  test  and  the  Rose- 
Gottlieb  test  gave  practically  the  same  results. 

The  conclusion  was  that  with  machines  run  at  the  lower 
speeds  a  little  water,  or  water  and  acid,  remains  suspended  in  the 
fat,  and  that  it  requires  the  force  created  by  the  higher  speed 
machine  completely  to  separate  this  from  the  fat. 

Babcock  Test  of  Buttermilk  and  Skim-milk — The  American 
Association  Test. — In  an  exhaustive  investigation  of  the  losses 
of  fat  in  buttermilk,  conducted  by  Professor  J.  W.  Mitchell 
.under  the  direction  of  the  senior  author  and  not  yet  completed, 
several  points  have  come  prominently  to  the  fore. 

The  first  of  these  is  that  the  losses  of  fat  in  buttermilk,  in 
our  creameries,  are  much  greater  than  they  are  generally  sup- 
posed to  be.  Many  creameries,  under  their  methods  of  testing, 
are  getting  tests  of  .1  per  cent  to  .2  per  cent  fat  for  their  butter- 
milk. Of  between  250  and  300  complete  records,  made  by 
Professor  Mitchell  and  the  author,  of  churnings  at  different 
creameries,  not  one  showed  a  Babcock  test  as  low  as  .2  per  cent. 
Of  course  the  test  was  rigorous,  but  even  this  was  considerably 
below  the  chemical  analysis. 

The  second  point  is  that  there  are  a  large  number  of  factors 
which  influence  the  per  cent  of  fat  in  the  buttermilk,  such  as 
length  of  time  taken  to  churn,  temperature  of  cream,  length  of 
time  the  cream  is  held  at  churning  temperature,  condition  of 
cream,  fullness  of  churn,  speed  of  churn,  etc.     This  means  that 


102  GRADING  AND  TESTING  MILK  AND   CREAM 

every  creamery  has  its  own  conditions  and  problems  to  meet,  and 
consequently  should  be  in  a  position  to  determine,  readily  and 
accurately,  what  its  losses  of  fat  in  the  buttermilk  are.  It  will 
then  be  in  a  position  to  study  how  to  reduce  them. 

The  third  point  is  that  the  average  creamery,  under  its 
methods  of  testing,  is  not  aware  of  what  its  losses  are.  It  is  not 
uncommon  to  note,  in  creamery  records,  tests  of  .1  per  cent  to 
.2  per  cent  for  the  buttermilk,  whereas  it  is  known,  from  hun- 
dreds of  analyses  made  in  the  laboratory  of  the  American  Asso- 
ciation of  Creamery  Butter  Manufacturers,  that  the  average 
loss  exceeds  .5  per  cent  fat.  The  loss  does  not  fall  far  short  of  a 
pound  of  butter  to  every  hundred  pounds  of  buttermilk. 

Realizing  the  necessity  for  a  simple  test  that  would  corre- 
spond closely  with  chemical  analysis  for  buttermilk  (or  skim- 
milk)  ,  and  that  could  be  operated  by  anyone  capable  of  conduct- 
ing a  Babcock  test,  the  senior  author  asked  Professor  Mitchell  to 
devise  such  a  test,  if  possible.  In  his  efforts  he  has  fortunately 
been  very  successful. 

The  different  methods  of  making  a  Babcock  test  of  butter- 
milk, including  the  new  modification  of  the  same,  are  briefly  out- 
lined below. 

The  following  method  of  testing  buttermilk  (or  skim-milk) 
has  been  in  use  for  many  years,  and  is  still  more  generally  used 
than  any  other.  A  double-necked  skim-milk  bottle,  graduated 
to  read  as  close  as  .01  per  cent  for  18  grams,  is  used.  Most  of 
the  bottles  read  up  to  .25  per  cent — some  to  .50  per  cent.  After 
the  buttermilk  is  well  mixed,  a  17.6  c.c.  pipette  is  used  to  transfer 
18  grams  of  it  to  the  test  bottle.  To  this  is  added  20  c.c.  of 
commercial  sulphuric  acid  (sp.  gr.  1. 82-1 .83).  The  acid  and  milk 
are  then  thoroughly  mixed  by  giving  the  bottle  a  gentle,  rotary 
motion.  Care  must  be  exercised,  in  mixing,  to  avoid  choking 
the  small  neck  and  causing  some  of  the  contents  to  be  thrown 
out  through  the  large  neck.  The  bottle  is  then  placed  in  the 
centrifuge  and  whirled  at  full  speed  for  about  five  minutes. 
Hot  water  (soft  or  distilled)  is  then  added  to  the  bottle  to  fill  it 
almost  to  the  neck  and  the  machine  is  again  run  for  one  or  two 
minutes.     Hot  water  is  then  added  to  float  the  fat  into  the  small 


AMERICAN  ASSOCIATION  TEST  103 

neck  and  the  bottle  is  again  whirled  for  one  or  two  minutes. 
The  bottle  is  then  placed  in  hot  water  at  a  temperature  of  1300- 
1400  F.,  after  which  the  reading  is  taken.  It  is  advisable  to  use  a 
pair  of  dividers  to  measure  the  fat  column.  Under  this  method 
the  reading  will  be  very  low — possibly  .1  per  cent  to  .2  per  cent 
when  it  should  be  .4  or  .5  per  cent. 

A  More  Rigorous  Test. — A  modification  of  the  foregoing  is  to 
take  a  9-gram  sample  by  means  of  a  9  c.c.  pipette,  that  is,  a 
half  sample.  To  this  is  added  about  1 2  c.c.  of  a  fairly  strong  acid, 
well  up  to  a  sp.  gr.  of  1.83.  The  whirling  is  done  in  a  very  high- 
speed machine  and  is  greatly  prolonged — fifteen  to  twenty  min- 
utes the  first  time,  about  ten  minutes  at  the  second  whirling,  and 
about  five  minutes  at  the  third  whirling,  or  thirty  to  thirty-five 
minutes  in  all.  The  reading  must  be  doubled,  since  only  a  9-gram 
or  half  sample  is  taken  to  a  test.  This  method  will  probably 
double,  or  more  than  double,  the  result.  But  even  under 
this  method  the  test  falls  considerably  below  the  results  secured 
by  chemical  analysis. 

The  American  Association  Test. — A  close  study  of  the  dif- 
ferent practical  methods  for  the  quick  determination  of  the  per 
cent  of  fat  in  milk  and  its  products  and  by-products  reveals 
the  fact  that  there  is  a  general  principle  running  through  them 
all,  that  is,  there  are  three  factors  which  operate  in  all  of  them. 
These  are  (1)  the  use  of  one  or  more  chemicals  to  liberate  the 
fat,  (2)  the  heating  of  the  contents  of  the  test  bottle  in  order 
to  liquefy  the  fat,  and  (3)  the  application  of  centrifugal  force. 
Where  sulphuric  acid  is  the  chief  or  only  chemical  used  it  gen- 
erates sufficient  heat,  through  its  strong  affinity  for  water;  but 
where  it  is  not  used  at  all  or  is  used  very  sparingly  it  becomes 
necessary  to  heat  the  sample  in  hot  water  before  centrifuging  it. 

A  number  of  useful  tests  have  been  devised  for  the  quick 
determination  of  the  per  cent  of  fat  in  milk,  etc.  The  following 
are  a  few  of  the  most  outstanding  of  these: 

(1)  The  Lactocrite,  devised  in  1886  by  Dr.  De  Laval,  inventor 
of  the  cream  separator  which  bears  his  name.  The  chemical 
used  was  concentrated  or  glacial  acetic  acid,  containing  5  per 
cent  of  concentrated  sulphuric  acid.     It  was  necessary  to  heat 


104  GRADING  AND   TESTING  MILK   AND   CREAM 

the  sample  before  centrifuging  it.     This  was  a  pioneer  test  but  is 
not  now  in  use. 

(2)  The  Babcock  test,  invented  by  Dr.  Babcock  of  the  Wis- 
consin Experiment  Station  and  published  in  July,  1890.  This 
test  is  so  widely  and  favorably  known  and  is  in  such  general 
use,  especially  in  America,  that  it  seems  unnecessary  to  do  more 
than  refer  to  it.  It  is  simple,  speedy  and  accurate,  and  the  cost 
of  a  test  is  small,  a  single,  cheap  chemical,  commercial  sulphuric 
acid,  being  used. 

(3)  The  Gerber  test,  brought  out  in  1892.  In  this  test  two 
chemicals  are  used,  viz.,  commercial  sulphuric  acid  and  amyl 
alcohol.     It  is  used  quite  extensively  in  Europe. 

(4)  The  Sinacid  Butyrometer.  This  test  was  devised  by 
Sichler  of  Germany  in  1904.  No  acid  is  used  in  the  test,  hence 
the  name  "  Sinacid."  The  chemicals  used  are  sodium  hydrox- 
ide, Rochelle  salt  and  iso-butyl  alcohol.  It  is  necessary  to  heat 
the  samples  by  placing  them  in  hot  water  before  centrifuging 
them. 

All  of  these  tests  were  designed  primarily  for  the  testing  of 
milk  and  such  milk  products  as  cream,  and  for  this  purpose 
they  are  reliable;  but  in  testing  the  by-products  of  the  dairy, 
skim-milk  and  buttermilk,  they  all  give  results  that  fall  con- 
siderably below  those  obtained  by  chemical  analysis  (the  Rose- 
Gottlieb  test).  No  doubt  this  is  the  main  reason  for  the  failure 
there  has  been  to  make  a  thorough  study  of  the  losses  of  fat  in 
buttermilk  and  how  to  overcome  them.  Hence,  when  the 
American  Association  of  Creamery  Butter  Manufacturers  began 
its  study  of  losses  of  fat  in  buttermilk  it  was  confronted  with 
the  problem  of  devising  a  suitable  test  for  the  accurate  deter- 
mination of  the  per  cent  of  fat  in  buttermilk, 

Trials  were  made  of  different  combinations  of  chemicals, 
such  as,  sulphuric  acid  and  amyl  alcohol,  sulphuric  acid  and  iso- 
butyl  alcohol,  and  sulphuric  acid  and  normal  butyl  (w-butyl) 
alcohol.  After  extensive  experiments  had  been  made  sulphuric 
acid  and  w-butyl  alcohol  were  selected  as  the  most  suitable 
combination  to  use,  and  for  the  following  reasons: 

(1)  The  results,  with  duplicate  tests,  are  exceptionally  uni- 


AMERICAN  ASSOCIATION  TEST  105 

form  and  correspond  closely  to  chemical  analysis  (The  Rose- 
Gottlieb  test),  as  the  accompanying  table  shows. 

(2)  There  is  much  less  trouble  with  a  deposit  in  the  test 
bottles  than  is  the  case  where  the  other  alcohols  are  used. 

(3)  Normal  butyl  (n-butyl)  alcohol,  being  a  single  alcohol 
that  is  readily  purified,  is  free  of  impurities  while  the  amyl  and 
iso-butyl  alcohols  are  not  likely  to  be.  In  blank  tests  made, 
that  is,  when  water  was  substituted  for  buttermilk  in  a  test,  a 
short  column  of  some  impurity  rose  into  the  neck  of  the  test 
bottle  when  the  amyl  and  iso-butyl  alcohols  were  used,  but  not 
when  w-butyl  alcohol  was  used. 

(4)  The  w-butyl  alcohol  is  quite  stable  and  is  not  at  all  likely 
to  be  attacked  by  the  sulphuric  acid,  while  the  other  alcohols 
mentioned  are  iso-alcohols  that  run  off  into  chains  and  are  less 
stable  and  are  likely  to  be  mixtures. 

(5)  The  w-butyl  alcohol  does  not  possess  either  a  pungent  or 
an  otherwise  offensive  flavor  or  odor,  and  consequently  is  much 
pleasanter  to  use  than  the  others. 

(6)  The  w-butyl  alcohol  is  the  lowest  in  price  of  the  dif- 
ferent alcohols,  and,  being  stable  and  free  of  impurities,  is  the 
most  reliable  alcohol  to  use.  Even  the  cheaper  grade  of  this 
alcohol  (the  "  practical  ")  contains  no  impurity  excepting  pos- 
sibly a  slight  amount  of  moisture. 

Extensive  and  carefully  conducted  investigations  have 
shown  that  the  right  amounts  of  commercial  sulphuric  acid 
and  w-butyl  alcohol  to  use  in  testing  a  9-gram  sample  of 
skim-milk  or  butter-milk  are  as  given  in  the  directions  which 
follow : 

Directions  for  making  a  test: 

Chemicals. — Commercial  sulphuric  acid. 
Normal  butyl  alcohol. 

1.  Place  the  chemicals  and  buttermilk  in  the  test  bottle  in 
the  following  amounts  and  the  order  indicated. 

(a)  2  c.c.  of  w-butyl  alcohol. 

(b)  9  c.c.  of  buttermilk. 

(c)  7  to  9  c.c.  of  commercial  sulphuric  acid. 

Vary  amount  of  acid  to  suit  its  strength.     The  right  amount 


106 


GRADING  AND  TESTING  MILK  AND   CREAM 


is  being  used  when  the  fat  column  is  golden  yellow  to  light  amber 
in  color. 

2.  Mix  contents  of  bottle  thoroughly. 

3.  Centrifuge  for  six  minutes. 

4.  Add  hot  water  (soft  or  distilled)  to  fill  bottle  to  bottom 
of  neck,  and  whirl  for  two  minutes. 

5.  Add  balance  of  water  to  float  fat  into  neck  and  again  whirl 
for  two  minutes. 

6.  Read  at  temperature  of  1300  to  1400  F.  Double  the  read- 
ing to  obtain  per  cent  of  fat. 

7.  In  cleaning  test  bottle — especially  if  there  be  any  deposit — 
first  add  a  small  amount  of  lukewarm  water  and  to  this  add 
sulphuric  acid.  Always  add  the  water  first  and  then  the^acid — 
never  the  reverse.  Rinse  the  bottle  well  with  this  mixture  and 
then  rinse  with  hot  water. 

This  test  gives  results  corresponding  to  those  of  chemical 
analysis. 

A  test  bottle,  with  a  scale  reading  up  to  .50  per  cent  for  18 
grams,  should  be  used. 

The  following  table,  comparing  the  Babcock,  The  American 
Association  Test,  and  Rose-Gottlieb  (Chemical)  tests,  is  sub- 
mitted. 


Babcock  Test  » 

The  American 

Rose-Gottlieb 

Association  Test 

Test 

Per  Cent 

Per  Cent 

Per  Cent 

•38 

•52 

•52 

34 

•47 

47 

40 

•57 

59 

43 

.60 

60 

36 

•54 

53 

39 

•56 

59 

36 

•50 

52 

34 

•5o 

48 

1  The  Babcock  test  given  in  the  foregoing  table  was  that  obtained  from  using 
12  c.c.  of  sulphuric  acid  with  a  9-gram  sample  and  centrifuging,  in  all,  about 
ihirty-five  ninutes  in  a  high-speed  tester. 


PER   CENT  OF   FAT  IN  BUTTER  107 

Determination  of  the  Per  Cent  of  Fat  in  Butter. — The  methods 
for  the  determination  of  the  per  cent  of  fat  in  butter  may  be 
classified  under  two  heads,  viz.,  ' 

(i)  Scientific  methods,  such  as 

(a)  The  Extraction  method. 

(b)  Rose-Gottlieb  method. 

(c)  Indirect  determination  of  fat. 
(2)  Practical  methods,  such  as 

(a)  The  90  per  cent  bottle  designed  by  Hepburn  for  use 
in  the  Babcock  test. 

(b)  The  Shaw  test. 

Scientific  Methods. — The  scientific  methods  are  too  com- 
plicated and  require  too  long  a  time  for  their  completion  to  be  of 
practical  use  in  a  creamery. 

The  Rose- Gottlieb  method  may  be  briefly  outlined  as  follows: 

This  method,  which  was  originally  designed  for  the  estima- 
tion of  fat  in  milk,  can  be  used  with  advantage  also  for  the  deter- 
mination of  fat  in  butter. 

According  to  A.  Hesse,1  about  2  grams  of  butter  are  weighed 
out  into  a  3  cm.  long,  half -cylindrical  glass  tube,  or  simply 
wrapped  in  a  piece  of  stiff  fat-free  paper  of  the  same  form.  The 
tube  or  paper  and  the  contained  fat  are  then  introduced  into  a 
Gottlieb  cylinder,  and  hot  water  is  added  until  the  10-cm.  mark 
is  reached.  If  the  butter  .does  not  melt,  the  cylinder  is  placed  in 
warm  water  until  it  does.  Then  1  c.c.  of  ammonia  and  10  c.c. 
of  95  per  cent  alcohol  are  added,  exactly  as  in  the  estimation  of 
milk-fat.  If  the  mixture  is  still  warm,  the  cylinder  is  cooled  in 
cold  water  so  that  the  ether  which  is  to  be  added  will  not  evap- 
orate too  quickly.  The  cooling  must  not,  however,  be  carried 
too  far;  otherwise  the  butter  will  become  solid  again.  Twenty- 
five  c.c.  of  ether  are  then  added,  and  the  contents  of  the  cylinder 
mixed  by  repeatedly  inverting  it.  Afterwards  25  c.c.  of  petro- 
leum ether  are  added  and  the  mixing  repeated. 

After  the  different  layers  have  separated  quite  sharply  from 
one  another,  the  clear  ether-fat  solution  is  siphoned  off  in  the 
usual  way,  the  lower  opaque  layer  not  being  disturbed.     Then 

1  Molkerei-Zeitung,  Hildesheim,  1903,  No.  27. 


108  GRADING  AND  TESTING  MILK  AND   CREAM 

50  c.c.  of  ether  are  poured  into  the  cylinder  and  at  once  siphoned 
off  without  being  mixed  with  the  other  liquid.  Finally,  the 
residual  liquid  is  shaken  with  a  mixture  of  25  c.c.  ether  and  25  c.c. 
petroleum  ether,  and,  after  settling,  the  ethereal  layer  is  drawn 
off.  The  three  portions  of  ether  are  naturally  all  placed  in 
the  same  tared  flask,  which  is  weighed  again  after  the  ether  has 
been  evaporated  and  the  fat  dried. 

These  repeated  extractions  with  ether  and  petroleum  ether 
are  necessary  if  exact  results  are  to  be  obtained.  If  the  above 
directions  are  carefully  followed,  it  will  be  found  that  the  Rose- 
Gottlieb  method,  while  easier  and  more  convenient,  and  also 
considerably  quicker  than  the  extraction  method,  gives  results 
which  are  in  very  close  agreement  with  those  obtained  by  the 
latter. 

The  Mojonnier  test  is  a  modification  of  the  foregoing,  and 
possesses  several  features  which  greatly  facilitate  the  work  and 
shorten  the  time  required  to  make  the  test.  In  the  method 
known  as  the  "  Indirect  Determination  of  Fat,"  the  percentages 
of  moisture,  casein  and  salt  are  carefully  determined.  These 
are  then  added  together  and  their  total  is  subtracted  from  100  to 
determine  the  per  cent  of  fat  in  the  butter. 

Practical  Methods. — There  are  several  practical  methods  that 
are  made  use  of  to  a  greater  or  less  extent.  We  shall  briefly 
outline  two  of  these. 

For  making  a  Babcock  test  of  butter,  using  the  Illinois  9-inch, 
9-gram,  90  per  cent  butter  test  bottle  devised  by  Dr.  N.  W. 
Hepburn,  University  of  Illinois,  the  following  directions  are  given: 

"  Taking  the  Sample. — In  testing  butter  it  is  necessary  to 
exercise  great  care  both  in  securing  and  in  preparing  the  sample. 

u  Sampling  from  a  Churn. — With  an  ordinary  ladle  cut  off 
the  surface  of  the  butter  in  several  places,  including  each  end  and 
the  middle  of  the  churn.  Then  make  a  composite  sample  by 
taking,  with  a  spatula  or  common  case  knife,  a  small  sample 
(10  to  20  grams  each)  from  six  or  eight  different  places  in  the 
churn  where  the  surface  has  been  removed,  putting  them  into 
an  8-ounce  wide-mouthed  glass-stoppered  bottle. 


PER  CENT  OF  FAT  IN  BUTTER 


109 


"  Sampling  from  a  Tub. — Draw  one  or  two  triers  from  the 
full  depth  of  the  tub  and  drop  the  entire  plug  of  butter  into  the 
glass-stoppered  bottle.  __ 

"  Preparing  the  Sample  for  Testing. — Place  the  glass-stoppered 
bottle  containing  the  sample  in  warm  water,  shaking  vigorously 
every  few  seconds  until  it  is  thoroughly  mixed  and  is  about  the 
consistency  of  heavy  cream,  when  it  is  ready  to  be  weighed  into 
test  bottle.  Caution. — Be  careful  not  to  get 
the  sample  too  warm  nor  in  too  liquid  a  condi- 
tion. If  this  happens  place  it  in  cold  water, 
shaking  very  frequently,  until  the  sample  takes 
on  the  desired  consistency.  Samples  should  not 
pour  freely,  but  like  thick  cream  or  paste.  Little 
heating  and  thorough  shaking  is  the  rule  for  suc- 
cess in  preparing  the  sample. 

"  Weighing  the  Sample. — Balance  the  bottle 
on  the  scales  and  weigh  out  a  9-gram  sample  by 
the  method  used  in  weighing  cream  samples. 
(Scales  as  sensitive  as  moisture-test  scales 
should  be  used.) 

"  Adding  Acid. — First  add  about  9  c.c.  of 
water  then  17.5  c.c.  of  sulphuric  acid.  Caution. 
— Add  the  acid  slowly  and  in  small  portions, 
shaking  after  adding  each  portion  to  avoid 
foaming.  High-salt  samples  are  most  likely  to 
foam.  If  foaming  occurs,  vigorous  shaking  will 
often  prevent  the  loss  of  the  sample.  After  the 
sample  is  thoroughly  mixed  with  the  acid  and  is 
dark  brown  in  color,  add  warm  water,  filling  the 
test  bottle  up  to  the  base  of  the  neck. 

"  Whirling. — Place  the  test  bottles  in  the 
tester  and  whirl  for  ten  minutes;  stop,  fill  with 
water  to  bring  the  fat  up  in  the  graduated  neck, 
and  whirl  again  for  five  minutes. 

"  Reading. — Set  the  test  bottle  in  water  at 
1400  F.,  covering  the  fat  in  the  neck,  and 
allow  it  to  stand  for  at  least  five  minutes;  then  read.     In  read- 


H 


Fig.  27. — Illinois 
9  inch,  9  gram, 
90  per  cent 
butter  test 
bottle. 


110  GRADING  AND  TESTING  MILK  AND   CREAM 

ing,  cut  off  all  the  upper  curve  on  the  fat  column  or  add  a 
couple  of  drops  of  white  mineral  oil  (glymol)  to  destroy  the 
meniscus. " 

THE    SHAW   TEST   FOR   FAT  IN   BUTTER 
APPARATUS  REQUIRED 

"  Babcock  centrifuge  or  tester.1 

"  Shaw  separatory  funnels. 

"  Balance  which  is  sensitive  to  o.oi  gram.  (A  torsion  bal- 
ance, such  as  is  used  in  testing  for  moisture,  will  answer  if  it  is 
in  good  condition.) 

"  Accurate  set  of  metric  weights. 


Fig.  28. — Separatory  funnels  used  in  the  Shaw  test. 

"  Glass  cylinder  graduated  at  9  and  11  c.c. 

"  ioo-c.c.  glass  beaker. 

"  Wooden  rack  for  holding  separatory  funnels. 

"  Support  for  separatory  funnels  on  balance. 

"  In  addition  to  the  above  a  special  socket  to  hold  the  separa- 
tory funnels  will  be  required.  As  shown  in  the  cut,  this  differs 
in  no  material  way  from  the  socket  ordinarily  used  in  the  Bab- 

*L.  F.  Nans. 


PER  CENT  OF  FAT  IN  BUTTER  111 

cock  centrifuge,  except  for  the  opening  in  the  side.  It  may 
easily  be  adapted  from  the  ordinary  socket  or  if  preferred  the 
socket  may  be  sent  to  us  and  we  will  make  the  necessary  changes 
for  a  nominal  charge.  Care  must  be  taken  that  the  capillary 
stem  of  the  funnel  does  not  project  far  enough  through  the  hole 
in  the  socket  to  strike  against  the  side  of  the  centrifuge  while 
being  whirled.  It  is  a  good  plan  to  fit  a  disk  of  rubber  gasketing 
in  the  bottom  of  the  socket. 

SAMPLING  THE   BUTTER 

"  In  the  determination  of  fat  in  butter,  great  care  must  be 
taken  in  securing  a  representative  sample  and  in  preparing  this 
for  the  test. 

"  Several  samples  from  different  parts  of  the  tub  or  churn 
should  be  taken  with  a  butter  trier.  These  are  placed  in  a  suit- 
able container,  such  as  a  i-pint  Mason  preserve  jar  or  a  cup, 
which  is  placed  in  water  at  about  ioo°  F.  The  sample  is  then 
mixed  with  a  spatula  or  spoon  until  about  the  consistency  of 
thick  cream.  The  sample  must  not  be  left  any  length  of  time  in 
open  containers,  since  some  of  the  moisture  will  evaporate. 
Should  the  sample  be  kept  for  any  reason  for  a  day  or  two 
before  it  is  mixed,  it  should  then  be  placed  in  warm  water  (with 
the  cover  on  the  container)  until  melted,  and  then  cooled  while 
being  vigorously  shaken  until  it  solidifies.  The  reason  for  this  is 
that  on  standing  some  of  the  water  will  ooze  out  and  cannot  be 
reincorporated  except  by  emulsifying  and  cooling  while  in  this 
condition.  Too  much  stress  cannot  be  laid  on  careful  sampling 
and  mixing  the  sample,  for  upon  this  the  accuracy  of  any  deter- 
mination in  butter  very  largely  rests. 

DETERMINING  THE   FAT 

"  It  will  be  found  more  economical  in  some  cases  if  four  or 
multiples  of  four  determinations  are  made  at  once.  In  this  case 
the  two  double  sockets  containing  the  funnels  will  balance  when 
placed  opposite  in  the  centrifuge.  If  but  one  or  two  determina- 
tions are  to  be  made  it  will  be  necessary  to  balance  the  centrifuge 
by  putting  weights  in  the  opposite  socket.     First  of  all,  the  clean 


112  GRADING   AND   TESTING  MILK  AND   CREAM 

and  dry  separatory  funnel  must  be  weighed,  and  this  as  well  as  the 
other  weighings  involved  must  be  done  with  care.  This  weight 
once  found  will  suffice  for  all  determinations  made  with  that  par- 
ticular funnel,  unless  by  accident  some  of  the  glass  should  be 
chipped  off.  A  slight  scratch  made  with  a  file  can  serve  to  iden- 
tify the  funnels.  A  paper  label  should  not  be  used.  If  requested 
at  the  time  of  ordering  we  will  number  them  without  additional 
charge. 

"  Each  time,  before  using  the  separatory  funnels,  they  should 
be  lubricated  with  a  properly  prepared  stopcock  lubricant  which 
we  supply  with  directions  for  its  use. 

"  I.  Weighing  the  Charge. — Counterpoise  the  small  beaker 
on  the  balance  and  carefully  weigh  out  20  grams  of  the  sample 
mixed  as  directed. 

"  II.  Transferring  the  Charge  to  the  Separatory  Funnel. — 
Place  the  beaker  containing  the  charge  on  a  radiator  or  steam 
pipe  until  the  butter  is  melted.  (This  may.  also  be  accom- 
plished by  adding  a  small  quantity  of  boiling  water.)  Next 
pour  the  charge  into  the  funnel  kept  in  an  upright  position  in  the 
wooden  rack.  No  part  of  the  charge  must  be  lost  in  transferring. 
With  a  fine  stream  of  hot  water  rinse  down  the  sides  of  the 
beaker  and  pour  the  rinsings  into  the  funnel.  (If  the  salt  is  to 
be  determined,  distilled  water  must  be  used.  See  directions 
under  '  Salt  Test.')  Repeat  this,  using  not  more  than  a  tea- 
spoonful  of  water  at  a  time  until  the  funnel  is  full  to  within 
about  one-quarter  of  an  inch  of  the  shoulder.  The  rinsing  can 
be  done  very  conveniently  with  the  arrangement  on  many  steam 
centrifuges  for  rilling  the  Babcock  test  bottles,  i.e.,  the  rubber 
tube  ending  in  a  glass  or  metal  point  and  connecting  with  a  water 
tank  heated  by  steam.  The  point  must  be  fine,  however.  Should 
it  be  larger  than  three-sixteenths  of  an  inch,  it  can  be  replaced 
with  the  tip  of  a  small  oil  can.  Should  this  arrangement  not  be 
at  hand,  one  can  easily  be  improvised  from  a  tin  can,  a  rubber 
tube,  and  an  oil-can  tip.  In  transferring  the  melted  butter 
and  rinsings,  the  last  drop  may  be  prevented  from  running  down 
the  outside  of  the  beaker  by  touching  the  lip  of  the  beaker  to  the 
neck  of  the  separatory  funnel. 


PER  CENT  OF  FAT  IN  BUTTER  113 

"  III.  Centrifuging. — Insert  the  separatory  funnel  in  the 
special  socket,  allowing  the  stem  to  project  through  the  hole  in 
the  bottom  and  the  handle  of  the  stopcock  through  the  open  side. 
Caution. — The  socket  must  always  be  placed  in  the  centrifuge, 
with  the  open  side  facing  the  direction  in  which  the  wheel  revolves. 
This  is  very  important,  if  the  opening  faces  the  reverse  direction 
the  stopcock  will  be  thrown  out  and  broken.  Whirl  one  minute 
at  the  same  speed  used  in  testing  milk  with  the  Babcock  test. 
The  centrifuge  must  be  kept  warm. 

"  IV.  Removing  the  Water. — Remove  the  separatory  funnel 
from  the  socket  and  allow  the  water  to  flow  through  the  stopcock 
until  the  fat  (or  curd)  is  within  one-eighth  of  an  inch  of  the  stop- 
cock. In  this  and  later  operations  involving  the  stopcock  one 
must  be  sure  it  does  not  stick.  It  must  always  be  under  control, 
and  it  is  best  to  give  it  frequent  slight  movements  when  the  water 
or  acid  is  running  through  it  to  be  sure  that  this  control  is  main- 
tained; otherwise  it  might  stick  at  a  critical  moment  and  the 
determination  be  lost.  The  most  of  the  salt  and  part  of  the  curd 
are  taken  out  by  the  water.  The  remainder  of  the  curd  and  all 
of  the  fat  stays  in  the  funnel.  If  it  is  desired  to  determine  the 
salt,  this  wash  water  is  allowed  to  run  into  a  250  c.c.  flask  and  the 
operation  described  in  this  paragraph  conducted  three  times 
instead  of  but  once,  the  wash  water  being  added  each  time  to 
the  flask. 

u  It  sometimes  happens  that  the  water  will  not  start  flowing 
when  the  stopcock  is  opened,  in  which  case  it  can  be  started  by 
blowing  into  the  mouth  of  the  separatory  funnel. 

44  V.  Dissolving  the  Curd. — Measure  out  9  c.c.  of  cold  water, 
preferably  condensed  steam,  with  the  glass  graduate  and  pour 
into  the  beaker.  Add  to  this  1 1  c.c.  of  sulphuric  acid  of  the  same 
strength  used  in  testing  milk  and  cream  (specific  gravity,  1.82- 
1.83)  and  mix  by  gently  shaking.  (Caution. — Always  add  acid 
to  water  and  not  water  to  acid,  or  a  serious  accident  may  result.) 
While  still  very  hot  add  the  mixture  to  the  contents  of  the  separa- 
tory funnel.  Now  dissolve  the  curd  by  giving  the  funnel  a 
circular  motion  with  the  hand  grasping  the  neck.  Centrifuge 
one  minute,  as  before.     Draw  off  the  acid  solution  till  the  fat 


114  GRADING  AND  TESTING  MILK  AND   CREAM 

layer  is  within  about  one-fourth  of  an  inch  of  the  stopcock  and 
repeat  the  operations  in  this  paragraph. 

"  VI.  Freeing  the  Fat  from  the  Acid  Solution.— The  fat  will 
now  be  in  a  clear  transparent  layer  free  from  curd,  and  the  solu- 
tion below  it  will  be  practically  colorless.  To  separate  these  two 
draw  off  the  latter  until  the  fat  nearly  reaches  the  stopcock  and 
centrifuge  another  minute.  Now  allow  the  fat  to  come  down 
through  the  stopcock  till  it  just  reaches  the  end  of  the  capillary 
stem.  This  last  step  offers  no  difficulties,  providing  the  stopcock 
is  kept  in  control,  but  it  requires  care.  If  desired,  the  acid  may 
be  colored  with  methyl  orange. 

11  VII.  Determining  the  Percentage  of  Fat. — Carefully  dry 
the  separatory  funnel  on  the  outside  with  a  clean  soft  cloth  and 
weigh  it.  The  weight  thus  obtained  minus  ihe  weight  of  the 
empty  funnel  represents  the  weight  of  butter-fat  in  20  grams  of 
the  sample.     The  percentage  is  obtained  by  multiplying  by  5. 

"  Often  it  is  possible  to  obtain  a  clear  fat  layer  with  but  one 
addition  of  acid,  but  in  some  cases  it  will  be  found  necessary  to 
add  it  the  second  time,  as  directed.  The  test  for  fat  alone 
involves  4  centrifugings  of  one  minute  each.  The  centrifuge 
should  be  kept  warm  and  the  contents  of  the  funnel  in  a  melted 
state  when  the  acid  is  added.  The  time  consumed  should  not  be 
longer  than  it  takes  to  test  cream  with  the  Babcock  test,  and  the 
operations  involved  are  simple  and  easily  learned.  No  difficulty 
will  be  experienced  in  obtaining  a  clear  fat.  Occasionally  there 
will  appear  a  slight  emulsion  at  the  bottom  of  the  fat  layers 
when  the  fat  is  drawn  into  the  stem.  This  is  so  small  in  amount 
that  it  does  not  seem  to  affect  the  accuracy  of  the  test  to  any 
considerable  extent.  The  emulsion  should  be  weighed  as  fat  and 
considered  as  such. 

CLEANING  THE  SEPARATORY  FUNNELS 

"  The  separatory  funnels  should  be  washed  after  each  deter- 
mination, but  it  is  not  necessary  to  dry  them  before  use,  providing 
their  weight,  when  clean  and  dry,  has  been  found.  The  cleaning  is 
easily  done  with  hot  water  and  either  soap  or  cleansing  powder. 
They  should  be  well  rinsed  off  with  clean  water  and  drained." 


GRADING  AND  TESTING  MILK  AND  CREAM  115 


•i  1 


Fig.  29. — Churn  room.     Kirschbraun  &  Son,  Omaha,  Neb.     One  of  the  largest 
and  finest  creameries  in  the  world. 


Fig.  30. — Street  view  of  the  first  prize  co-operative  creamery  at  Carroll,  Iowa. 


116 


GRADING  AND  TESTING  MILK  AND  CREAM 


Very  few  of  the  creameries  have,  as  yet,  begun  the  regular 
determination  of  the  per  cent  of  fat  in  their  butter,  most  of  them 
confining  their  work  on  the  composition  of  butter  to  determina- 
tions of  the  per  cent  of  moisture  and  the  per  cent  of  salt.  The 
three  constituents  of  butter  outside  the  fat,  are  moisture,  salt 
and  curd;  and  where  a  uniform  system  of  manufacture  is  adopted, 
and  the  churning  is  done  under  right  conditions  and  the  butter 
well  washed,  the  curd  content  is  not  likely  to  exceed  i  per  cent 


.  31.— The  oil-test  churn. 


or  vary  more  than  half  a  per  cent.  Consequently  accurate 
determination  of  the  moisture  and  salt-contents  enables  a 
creamery  to  estimate,  very  closely,  the  per  cent  of  fat  in  the 
butter. 

Sediment  Test. — Milk  should  be  free  from  sediment  and 
foreign  insoluble  material.  Producers  of  the  raw  material  are 
not  always  conscious  of  the  necessity  of  producing  clean  milk, 
and  of  the  effects  of  impurities  upon  the  finished  products. 

Sediments  may  be  seen  on  the  bottom  of  a  glass  jar  after  the 


NECESSITY  OF   GOOD    MILK 


117 


milk  has  stood  quietly  for  several  hours.  The  better  way  of 
showing  these  sediments  is  to  use  the  Wisconsin  Sedimentation 
Test.  The  container  for  this  test  holds  about  one  pint  of  milk. 
A  screw  cap  fits  over  the  top.  By  means  of  a  small  air  pump, 
pressure  can  be  applied  and  the  milk  forced  through  a  disk  or 
filter.  This  disk  is  removable  and  the  filtered-out  dirt  on  the 
surface  can  thus  be  shown. 

Necessity  of  Good  Milk. — All  authorities  agree  that  the  best 
grade  of  butter  and  cheese  cannot  be  made  from  sour  or  tainted 
milk.     The  two  countries  renowned  for  the  excellence  of  their 


^lAsU 


*—'■  i  TTlniil,,   -«M| 

ill  lift 


Fig.  32. — Wizard  tester.  Fig.  33. — Twentieth-century  hand  tester. 


dairy  products — Denmark  and  Canada — owe  their  success 
largely  to  the  purity  of  the  milk  from  which  these  products  are 
made.  Makers  who  have  won  for  themselves  national  reputa- 
tions in  cheese-  and  butter-making  have  almost  invariably  been 
men  who  insisted  on  getting  first-class  milk.  The  method  of 
classifying  milk  and  cream  and  paying  for  each  according  to 
quality  has  been  adopted  by  some  creameries. 

The  authors  do  not  hesitate  to  say  that  cream  whose  flavor 
is  such  as  to  show  that  it  is  in  a  putiefactive  or  decomposed 
condition  should  be  rejected  as  unfit  for  making  an  article  of 
human  food.     While  it  is  advocated  by  some  that  it  should  be 


118  GRADING  AND  TESTING  MILK  AND   CREAM 

received,  made  into  butter  and  sold  on  its  merits,  the  wisdom 
of  this  is  to  be  questioned.  Cream  that  is  simply  off  in  flavor  is  a 
different  proposition.  This  may,  in  justice  and  fairness,  be 
taken  in  on  its  merits  and  paid  for  accordingly.  The  practice 
of  receiving  and  paying  for  cream  indiscriminately  is  something 
which  should  be  condemned  and  discouraged.  The  authors  have 
come  in  contact  with  many  patrons  in  different  parts  of  the 
country  and  have  yet  to  meet  the  first  patron  who  would  seri- 
ously object  to  taking  his  milk  or  cream  home  when  thoroughly 
convinced  that  its  condition  was  such  that  it  should  not  be 
received.  Patrons,  as  a  rule,  respect  the  maker  who  keeps  his 
creamery  in  a  good  sanitary  condition  and  insists  upon  being 
supplied  with  a  good  quality  of  milk  or  cream.  It  should  be  the 
aim  of  every  creameryman  to  make  the  highest  grade  of  butter 
possible,  and  thus  be  in  a  position  to  take  full  advantage  of  a  dis- 
criminating market,  for  this  is  the  kind  of  market  that  pays  the 
highest  prices. 

Sampling  of  Milk. — The  sampling  of  milk  and  cream  for  fat 
tests  is  one  of  the  most  delicate  problems  with  which  the  creamery 
operator  has  to  deal.  If  a  proper  sample  is  not  obtained,  the 
ultimate  test  will  not  be  correct,  no  matter  how  carefully  the 
succeeding  steps  may  be  carried  out.  There  are  two  methods  of 
sampling  in  use:  First,  sampling  with  a  small  dipper,  and 
second,  sampling  with  a  sample-tube,  or  milk- thief.  The 
sampling  of  milk  for  composite  samples  should  be  done  every 
day,  and  the  samples  taken  should  represent  the  average  quality 
and  form  a  certain  proportionate  part  of  the  milk  or  cream 
delivered. 

In  order  to  get  a  sample  which  represents  the  average  quality, 
the  milk  or  cream  delivered  must  be  thoroughly  stirred,  so  as 
to  get  an  even  distribution  of  the  fat. 

In  order  to  get  a  proportionate  part  of  the  milk  or  cream 
delivered  from  day  to  day,  it  is  necessary  to  use  a  sampling- 
tube. 

The  sampling  of  milk  and  cream  with  a  dipper  for  composite 
samples  has  been  in  use  for  a  long  time,  and  is  still  practiced  to 
quite  an  extent.     However,  it  is  fast  becoming  recognized  that 


SAMPLING  OF  MILK  119 

the  use  of  a  suitable  sampling  tube  is  much  better.  It  takes  a 
more  representative  sample  of  a  can  of  cream,  whether  it  be  for 
the  making  up  of  a  composite  sample  or  for  the  testing  of  an 
individual  shipment.  In  the  case  of  composite  samples  of  both 
milk  and  cream  it  takes  an  aliquot  portion,  or  one  in  proportion 
to  the  quantity  of  milk  or  cream  delivered.  The  difficulty  at 
one  time  in  sampling  cream — and  particularly  thick  cream — 
with  the  sampling  tube  was  that  the  only  opening  in  the  tube 
was  at  the  bottom,  and  the  cream  would  not  flow  into  it  as  the 
tube  was  lowered.  However,  this  trouble  is  completely  over- 
come when  a  sampler  like  the  McKay  sampler  is  used.  This  is 
made  up  of  two  tubes,  an  inner  and  an  outer,  and  a  plunger 
(see  cut).  Both  the  tubes  have  openings  up  the  side.  Before 
inserting  the  sampler  in  a  can  of  cream,  the  outer  tube  is  turned 
on  the  inner  so  that  the  openings  are  not  opposite  each  other,  or 
so  as  to  close  the  sampler,  and  the  plunger  is  drawn  back.  The 
sampler  is  then  lowered  into  the  cream  to  the  bottom  of  the  can, 
when  it  is  opened  momentarily  to  allow  it  to  fill  and  is  then  closed 
again.  In  emptying  the  sampler  the  outer  tube,  which  is  the 
shorter  of  the  two,  is  drawn  up  a  little  to  leave  an  opening  at  the 
bottom,  and  the  plunger  is  pushed  down  to  force  the  cream  out  of 
the  tube.  In  doing  so  it  cleans  the  tube  completely.  This  style 
of  sampler  does  equally  efficient  work  whether  used  in  a 
creamery  or  cream  station,  or  in  taking  samples  on  a  cream 
route. 

An  investigation  made  by  the  American  Association  of  Cream- 
ery Butter  Manufacturers  showed  the  dipper  method  of  sampling 
cream  to  be  unreliable.  In  this  investigation  the  cream  in  the 
can  was  first  hand-stirred — no  less  than  forty  vigorous  double 
strokes  being  used — and  then  sampled  with  a  dipper,  after 
which  a  sample  was  taken  by  means  of  a  McKay  or  tube  sampler. 
In  all,  thirty-two  lots  of  cream  were  sampled  and  tested  in  this 
way,  and  the  following  short  table  gives  some  of  the  results 
secured: 


120 


GRADING   AND  TESTING  MILK  AND   CREAM 


Sample 

Times 

No. 

Stirred 

i 

5o 

2 

40 

3 

65 

4 

60 

5 

44 

6 

60 

7 

75 

8 

5o 

Condition  of  Cream 


Viscous,  not  very  smooth .  . 

Smooth  and  even 

Heavy  on  top,  liquid  below,  lumpy 

Viscous  but  good  condition 

Quite  liquid 

Viscous,  slightly  lumpy 

Top   fair,    bottom   almost   solid, 

lumpy 

Good  condition 


Babcock  Test  of 

Dipper 

Tube 

Sample 

Sample 

41.0 

44.0 

39o 

39-5 

42.5 

38.5 

34-5 

33-5 

26.5 

24-5 

40.5 

40.S 

47-5 

38.5 

40.5 

39-5 

Difference 


Per  Cent 
3-o 

0.5 
4.0 
1.0 
2.0 
0.0 

t9.o 
1.0 


While  the  difference  in  the  test  of  the  samples  under  the  two 
methods  was  usually  not  great,  yet  the  dipper  method  of  sampling 
proved  unreliable. 

Sampling-tube. — At  creameries  where  milk  is  received,  the 
sampling-tube,  or  milk-thief,  gives  the  best  results  and  satis- 
faction. It  is  very  difficult  in  practice  to  get  a  proportionate 
sample  with  a  dipper,  from  day  to  day.  To  illustrate:  A  patron 
who  delivers  200  pounds  of  milk  testing  3  per  cent  fat  one  day 
may  on  another  day  deliver  100  pounds  of  milk  testing  5  per  cent 
fat.  If  a  dipperful  is  taken  from  each  for  a  composite  sample,  the 
test  of  that  composite  sample  will  be  3  +  5-^2,  or  4  per  cent. 
According  to  this  test,  these  300  pounds  of  milk  delivered  will 
contain  12  pounds  of  butter-fat.  In  reality  6  pounds  of  fat  were 
delivered  in  the  200  pounds,  and  5  pounds  of  fat  in  the  100  pounds, 
making  a  total  of  1 1  pounds  of  fat.  Thus  we  see  that  the  dipper 
method  is  not  reliable,  and  in  this  case  the  patron  was  paid  for 
1  pound  of  butter-fat  too  much  for  the  two  days'  delivery.  If 
the  sample  taken  from  the  200  pounds  of  milk  had  been  twice  as 
great  as  that  taken  from  the  100  pounds  of  milk,  then  the  com- 
posite test  would  have  been  perfect,  no  matter  whether  it  had 
been  taken  with  a  dipper  or  with  a  sampling- tube.  If  the  same 
weighing-can   is  used  every  day,  it  is  possible    to  maintain  an 


SAMPLING  TUBE 


121 


M 

i  !    '  W*1 

u     -• 

\Wrr- 

^     \ 

Jt&^ 

y^^                      rfy 

.-' 

WKmM 

Fig.  34. — Vat   room.     Kirschbraun  &  Son,  Omaha,  Neb.      One  of   the  largest 
and  finest  creameries  in  the  world. 


Fig.  35. — Interior  of  creamery,  Strawberry  Point,  Iowa.     One  of  the  largest 
whole-milk  creameries  in  the  U.  S. 


122 


GRADING  AND   TESTING  MILK  AND   CREAM 


exact  proportion  for  a  sample  by  always  putting  the  sampling- 
tube  perpendicularly  into  the  milk  at  the  same  place  in  the  weigh- 
ing-can, and  by  exercising  care  in  other  respects. 

When  the  cream  is  being  collected  from  different  patrons 
by  a  hauler,  a  milk-thief  often  works  unsatisfactorily.  This  is 
especially  true  during  cold  weather.  A  cream  tube  similar  to 
the  one  shown  in  the  accompanying  illustration  is  more  effective. 


^Hf  «* 


Fig.  36. 


-The  McKay  cream  and 
milk  sampler. 


Fig.  37. — Cream 
sampling-tube. 


The  way  in  which  the  tube  is  used  is  apparent  from  the  figure. 
If  a  certain  patron  has  40  pounds  of  cream,  the  cream  is  filled 
to  the  40  mark  on  the  scale  of  the  tube;  if  he  has  30  pounds,  it  is 
filled  to  the  30  mark,  etc. 

Sampling  Churned  Milk. — It  occasionally  happens  that  the 
milk  arrives  at  the  creamery  slightly  churned.  This  is  espe- 
cially the  case  during  the  summer.  Usually  such  milk  is  sam- 
pled in  this  condition,  but  if  it  is  desired  to  find  ihe  percentage  of 
fat  in  such  milk  in  its  unchurned  condition,  it  is  essential  to  melt 


SOUR  AND   COAGULATED   MILK  123 

the  churned  fat  before  sampling.  If  the  butter  has  been  churned 
into  a  few  large  lumps,  these  lumps  can  be  taken  out  in  a  pan,  or 
pail,  with  a  comparatively  small  amount  of  milk,  and  this 
heated  until  the  butter  has  melted.  This  is  then  remixed  with  Ihe 
milk  from  which  it  was  first  taken  and  sampled  while  it  is  being 
stirred. 

The  churning  of  the  milk  during  transit  is  mainly  due  to 
two  things:  First,  to  a  high  temperature  of  the  milk  (65 °  to 
85 °  F.)  and  second,  to  hauling  partly  filled  cans  a  long  distance 
over  rough  roads.  If  the  temperature  of  the  milk  is  low  (about 
500  F.),  when  it  leaves  the  producer,  there  is  seldom  any  danger 
of  having  churned  milk  at  the  creamery. 

Frozen  Milk. — When  milk  is  cooled  to  31  °  F.,  or  below,  it 
freezes.  Ice  forms  near  the  sides  and  bottom  of  the  can,  until 
a  funnel-shaped  cavity  filled  with  milk  is  left  in  the  center. 
According  to  both  Richmond  and  Fleischmann,  the  icy  por- 
tion contains  more  water  than  the  unfrozen  milk,  and  the 
unfrozen  portion  is  rich  in  solids.  According  to  Farrington, 
when  25  per  cent  of  the  sample  of  milk  was  frozen,  the  icy 
portion  contained  about  1  per  cent  less  fat  than  the  original 
portion.  When  about  half  of  it  was  frozen  there  was  no  great 
difference  in  the  fat-content  of  the  frozen  and  unfrozen  parts. 

In  practice,  however,  freezing  seems  to  have  a  different  effect. 
When  a  can  full  of  partly  frozen  milk  is  sampled  at  the  creamery, 
the  unfrozen  milk  nearly  always  contains  less  fat  than  the  original 
sample.  This  can  be  accounted  for  by  opening  the  can  of  milk 
and  noting  the  amount  of  frozen  cream  on  the  sides  near  the  top. 
Whether  the  unfrozen  portion  contains  less  or  more  fat  than  the 
original  depends,  therefore,  upon  conditions.  At  any  rate, 
frozen  milk  has  a  composition  different  from  that  of  the  original 
sample.  On  this  account  an  accurate  sample  cannot  be  had, 
unless  the  frozen  portion  be  first  completely  melted  and  well 
mixed  with  the  remainder. 

Sour  and  Coagulated  Milk. — In  order  to  get  a  fair  sample 
from  a  can  of  sour  and  coagulated  milk,  it  must  be  stirred 
very  thoroughly,  so  as  to  bring  the  coagulated  milk  into  a 
uniform  emulsion.     A  better  sample  can  usually  be  obtained 


124 


GRADING  AND   TESTING  MILK   AND   CREAM 


with  a  dipper.  If  the  milk  is  not  too  thick,  a  fair  sample  can  be 
obtained  by  the  use  of  the  sampling- tube.  In  order  to  reduce 
a  can  of  coagulated  milk  to  a  thoroughly  uniform  quality,  it  is 
best  to  pour  it  from  one  can  into  another.  This  mixes  it  much 
more  completely  than  if  the  sample  were  simply  stirred  with  a 
dipper  or  any  other  kind  of  an  agitator. 

Apportioning  Skim-milk. — The  amount  of  skim-milk  to  be 


Fig.  38. — Jensen  can  drier,  sterilizer  and  rinser. 
(Jensen  Creamery  Machinery  Co.) 


received  by  the  patron  depends  largely  upon  the  thickness  of 
cream  skimmed,  and  upon  the  amount  of  skim-milk  retained  at 
the  creamery  for  various  purposes.  The  amount  of  skim -milk 
generally  returned  by  creameries  varies  between  80  and  90  per 
cent  of  the  whole  milk  delivered. 

Most  up-to-date  creameries  now  make  use  of  skim-milk 
weighers.  Where  such  are  employed,  the  man  who  receives  the 
milk  hands  each  patron  a  check  for  the  amount  of  milk  delivered. 
This  check  is  put  into  the  skim-milk  weigher,  and  it  allows  an 


WASHING  CANS 


125 


amount  of  skim-milk  to  flow  out,  corresponding  to  the  number  of 
pounds  indicated  on  the  check. 

In  case  a  skim-milk  weigher  is  not  employed,  it  is  essential 


Fig.  39. — Hydraulic  can  washer  and  dryer.     (Creamery  Package  Mfg.  Co.) 

to  have  a  man  at  the  skim-milk  tank  to  weigh  out  the  proper 

amount  of  skim-milk  to  each  patron.     If  the  patrons  are  allowed 

to  weigh  out  their  own  skim-milk,  mistakes  are  frequently  made, 

which  result  in  more  or  less  dissatisfaction.     It  is  quite  customary 

for  butter-makers  to 

draw  a  chalk  line  on 

the  outside  of  the  can 

some  distance  below 

the     surface    of     the 

milk.     This  indicates 

the  point  to  which  the 

can  may  be  filled  with 

skim-milk. 

Washing  Cans. — 
The  creamery  oper- 
ator should  make  it 
a  point  to  have  all 
empty  cans  thorough- 
ly washed  with  warm 
water,  and  then 
steamed    and    steril- 


Fig.  40. — Hydraulic  can  washer- rotary  type. 
(Rice  and  Adams.) 


ized,  after  which  hot  air  should  be  blown  through  thoroughly  to 
dry  the  cans.  Frequently,  bad  flavors  are  transmitted  to  cream 
from  cans  that  have  been  closed  up  tight  before  being  thoroughly 


126  GRADING  AND  TESTING  MILK  AND   CREAM 

dried.  Where  hot  air  is  not  used,  the  cans  can  be  turned 
upside-down  on  a  platform  with  openings  to  allow  air  to  circu- 
late through  the  cans,  drying  them  thoroughly  before  the  covers 
are  put  on. 

Drying  cans  as  above  described  not  only  conserves  the  tin 
of  the  cans,  but  also  places  the  cans  with  the  patrons  in  a  clean 
condition,  free  from  bad  odors.  It  also  saves  considerable 
work  on  the  part  of  the  patrons,  as  well  as  insuring  them  a  clean, 
sanitary  can. 

One  patron  told  the  author  that  this  cleaning  of  the  can  was 
worth  one  cent  per  pound  of  butter-fat  to  him.  The  creamery 
is  equipped  to  do  this  can-cleansing  better  than  is  the  patron 
and  it  is  repaid  for  this  extra  labor  in  a  better  grade  of*  cream 
and  in  increased  patronage. 


CHAPTER  IX 
COMPOSITE  SAMPLES 

Definition. — In  order  to  avoid  testing  each  patron's  milk  or 
cream  every  day  for  fat,  a  small  sample,  which  represents  the 
average  quality  and  a  proportionate  part  of  the  whole,  is  taken 
from  each  patron's  milk  every  day  and  placed  in  a  jar.  A  pre- 
servative of  some  kind  is  previously  placed  in  the  jar  to  keep  the 
contents  from  spoiling.     This  is  called  a  composite  sample. 

When  to  Sample. — Some  makers  prefer  to  sample  the  milk  or 
cream  delivered  every  day;  others  prefer  to  sample  every  other 
day.  Some  creamery  operators,  again,  sample  four  or  five  times 
in  succession  at  intervals,  the  patrons  being  unaware  of  the  time 
when  the  sampling  is  to  take  place.  The  most  reliable  and  prac- 
tical method,  however,  is  to  take  a  sample  every  day,  and  test  it 
for  fat  at  the  end  of  every  two  weeks.  When  cream  is  received 
composite  samples  do  not  give  reliable  results.  In  fact  this 
system  has  been  very  generally  superseded  by  that  of  weighing 
and  testing  the  cream  of  each  delivery  or  shipment. 

Kind  of  Preservatives  to  Add.  While  there  are  several  pre- 
servatives that  may  be  used,  such  as  salicylic  acid,  borax,  boracic 
acid,  and  bicarbonate  of  soda,  those  most  commonly  used  are 
bichromate  of  potash  and  corrosive  sublimate  (mercuric  chloride) 
either  singly  or  as  a  mixture.  Bichromate  of  potash,  while 
poisonous,  is  not  extremely  so  and  it  imparts  a  color  to  the  sample 
which  readily  indicates  its  presence.  It  has,  however,  two 
defects;  if  used  in  excess  it  is  very  much  inclined  to  cause  a 
charred  or  burnt  reading  when  the  sample  is  tested,  and  if  the 
sample  be  exposed  to  light  for  any  length  of  time  a  leathery  scum 
forms  on  the  surface,  which  it  is  difficult  to  dissolve  completely 
by  means  of  the  sulphuric  acid. 

127 


128 


COMPOSITE   SAMPLES 


Corrosive  sublimate  is  a  strong  and  a  very  satisfactory 
preservative;  but  it  is  quite  poisonous,  and  where  the  powder 
itself,  which  is  white,  is  used  in  composite  samples  some  kind  of 
coloring  matter  should  always  be  added  to  indicate  its  presence. 
According  to  the  authors'  experience,  corrosive  sublimate 
tablets  can  be  highly  recommended.  The  tablets  contain  a 
color,  which,  when  dissolved,  colors  milk,  so  that  it  can  readily 
be  distinguished  as  not  being  fit  for  human  food.     The  tablets  are 

very  poisonous,  but  are  more 
efficient  in  their  preservative 
effect  than  bichromate  of 
potash.  They  can  be  ob- 
tained from  any  creamery- 
supply  house. 

During  the  winter,  when 
the  samples  are  kept  com- 
paratively cold,  less  perserva- 
tive  is  needed  than  in  the 
summer.  One  corrosive  sub- 
limate tablet  will  keep  a 
half-pint  to  a  pint  of  milk 
or  cream  in  good  condition  for  about  two  weeks  in  summer, 
and  about  three  weeks  in  winter,  providing  the  sample  is  properly 
cared  for.  Some  makers  are  practicing  testing  at  the  end  of 
every  month  during  the  winter,  and  every  two  weeks  during  the 
summer.  Testing  at  the  end  of  every  month  saves  labor,  but  it 
is  not  a  reliable  method  to  follow  under  all  conditions,  as  some  of 
the  samples  are  likely  to  be  somewhat  impaired  after  standing 
so  long. 

Arrangement  of  Composite  Samples. — Pint  glass  jars  with 
covers  are,  so  far  as  known,  the  most  convenient  vessels  to  use 
for  composite  samples.  Shelves  should  be  arranged  in  the  weigh- 
ing-room on  which  to  keep  the  bottles.  If  possible,  it  is  best 
to  have  them  in  a  case  closed  with  glass  sliding  doors.  This 
is  neat,  and,  if  the  glass  doors  fit  well,  the  samples  are  in  some 
measure  protected  in  case  of  quick,  unexpected  changes  in  tem- 
perature.    These  sliding  doors  should  be  locked  when  the  cream- 


MMmmm 


T 


Fig.  41. 


-Composite  samples  and  rack  to 
hold  sample  jars. 


CARE  OF  COMPOSITE  SAMPLES  129 

ery  operator  is  absent  from  the  creamery,  in  order  to  prevent  any 
tampering  with  the  composite  samples. 

The  best  method  of  arranging  the  sample  jars  is  to  have  all 
the  jars  belonging  to  the  patrons  of  each  route  standing  in 
one  group,  or  on  one  shelf,  if  possible.  The  bottles  are  num- 
bered to  correspond  with  the  number  given  each  patron  on  the 
milk  sheet.  The  name  of  the  hauler,  or  the  number  of  the  route 
can  be  put  on  each  shelf.  The  samples  belonging  to  those  who 
haul  their  own  milk  can  be  put  on  another  shelf;  these  can  be 
designated  as  individual  haulers.  Such  a  classification,  when  the 
bottles  are  plainly  numbered,  will  often  prevent  the  mistakes  that 
are  likely  to  occur  if  the  bottles  are  simply  numbered  and  put 
into  a  rack  together. 

Care  of  Composite  Samples. — In  the  first  place,  the  jars 
should  be  kept  scrupulously  clean.  The  tests  are  unreliable  if 
the  jars  are  left  covered  with  milk  and  molds  round  the  neck 
from  one  month  to  another.  When  the  samples  have  been 
tested  the  jars  should  be  thoroughly  cleaned,  and,  if  necessary, 
scalded,  before  they  are  used  again.  Care  should  be  taken  to 
spill  as  little  milk  as  possible  around  the  neck,  inside  as  well 
as  outside  of  the  bottle,  when  the  sample  is  put  in.  If  the 
milk  is  spilled  there,  it  gives  the  bottle  an  unattractive  appear- 
ance. Very  often  it  becomes  moldy,  and,  as  more  milk  is  added 
and  the  sample  shaken  every  day,  this  mold  gradually  extends 
down  the  sides  of  the  bottle.  This  causes  the  composite  sample 
to  be  infested  with  undesirable  growth,  and  to  spoil  sooner  than 
it  would  if  greater  care  were  taken  in  keeping  the  milk  from 
coming  in  contact  with  the  sides  of  the  bottle  before  coming 
in  contact  with  the  preservative. 

A  few  drops — but  only  a  few — of  formaldehyde  added  to  the 
sample,  where  this  is  necessary,  is  a  good  preventive  of  mold; 
but  this  should  not  be  used  as  a  substitute  for  thorough  cleaning 
of  the  bottles  after  each  test  period. 

It  is  important  also  that  the  sample  jars  be  well  covered; 
otherwise  the  moisture  evaporates,  causing  the  milk  or  cream 
to  dry  up,  and,  making  the  test  unreliable  by  increasing  the  per 
cent  of  butter-fat.     A  gentle  rotary  motion  should  be  given  each 


130  COMPOSITE   SAMPLES 

jar  when  a  sample  is  added  to  it  to  mix  the  cream,  which  rises  to 
some  extent  after  the  milk  has  stood  a  while. 

Average  Sample. — It  is  sometimes  desirable  to  obtain  an 
average  test  of  the  milk  from  a  whole  day's  delivery.  This  can 
be  obtained  in  two  ways:  First,  by  taking  a  sample  from  each 
patron's  milk  with  a  sampling- tube,  and  putting  all  the  samples 
together  in  one  jar.  The  result  represents  an  average  test,  pro- 
viding the  samples  have  been  correctly  taken.  Second  an  aver- 
age test  can  be  had  by  boring  a  small  hole  in  the  conductor-head. 
When  the  milk  passes  over  this  hole,  a  small  portion  of  it  drops 
through.  A  vessel  of  some  kind  can  be  put  underneath  to  catch 
the  drops.  Such  a  drip-sample  will  represent  very  accurately 
the  average  quality  of  the  milk  received  at  the  creamery.  If  it  is 
desirable  to  keep  this  sample,  a  preservative  can  be  added  to  it. 

Composite  Sampling  without  the  Use  of  Preservatives. — 
Pipettes  can  be  obtained  holding  5.87  c.c.  of  milk.  These  are 
one- third  the  size  of  the  ordinary  17.6  c.c.  pipette  used  for  the 
Babcock  test.  With  this  small  pipette  a  sample  may  be  taken 
every  day  from  each  patron's  milk,  during  three  successive  days, 
and  emptied  into  the  same  test-bottle  each  day.  At  the  end  of 
three  days  the  samples  may  be  tested  and  the  bottles  cleaned, 
ready  for  use  again. 

Accurate  composite  samples  may  be  obtained  in  this  way, 
providing  the  sample  in  the  pipette  is  correctly  taken  each  day. 
No  preservative  is  needed.  The  preservatives  are  added  to  the 
composite  samples  to  prevent  curdling.  The  test-bottles  may 
be  placed  on  a  shelf,  or  preferably  in  a  rack  made  to  hold  them. 
They  should  be  marked  in  such  a  way  as  to  identify  them. 
A  good  way  is  to  mark  them  as  the  composite  jars  are  marked, 
the  number  on  the  test-bottle  corresponding  to  the  number  on 
the  milk-sheet  for  each  patron. 


CHAPTER  X 


CREAMERY  CALCULATION 


Find  the  Average  Per  Cent  of  Fat. — In  calculating  the  average 
per  cent  of  fat  from  a  number  of  cows,  or  the  milk  furnished  by 
the  different  patrons,  the  mistake  of  adding  the  tests  of  all  the 
samples  together  and  dividing  the  sum  by  the  total  number  of 
samples  tested  is  often  made.  Milk  from  different  patrons,  or 
from  different  cows,  will  always  vary,  both  in  quality  and  in 
quantity,  and  in  order  to  get  a  correct  average  test,  both  quan- 
tity and  quality  must  be  taken  into  consideration.  The  wrong 
way  of  calculating  the  average  percentage  may  be  illustrated  as 
follows: 


Sample 

Milk  Delivered 

Per  Cent  Fat 

i 

50  lbs. 

5-o 

2 

100 

4-5 

3 

500 

3-o 

4 

300 

3-5 

4)16% 

4 

The  average  test,  according  to  the  wrong  method  =4  per  cent. 

The  correct  way  of  calculating  the  average  percentage  may 
be  illustrated  as  follows : 

The  average  test,  according  to  the  correct  method,  is  3.42 
per  cent. 

It  will  be  seen  from  the  example  quoted  that  there  is  a  differ- 
ence of  more  than  .5  per  cent.     If  the  percentage  of  fat  or  the 

131 


132 


CREAMERY  CALCULATION 


Sample 

Milk  Delivered 

Per  Cent  Fat 

i 

2 

3 

4 

50  lbs. 
100 
500 
300 

950  lbs. 

5.0=   2.5  lbs.  fat 

4-5=   4-5 
30=15.0 

3-5  =  io.5 
950)32.5  lbs.  fat 

3-42 

number  of  pounds  of  milk  is  uniform,  it  does  not  matter  which 
of  the  two  ways  illustrated  above  is  used.     But  as  uniformity 


Fig.  42. — A  Russian  co-operative  creamery  in  Siberia. 
(U.  S.  Government  Bulletin.) 


in  either  of  these  respects  scarcely  ever  exists  in  practice,  the  only 
correct  way  of  calculating  the  percentage  is  to  find  the  total 
number  of  pounds  of  fat  and  divide  it  by  the  total  number  of 
pounds  of  milk;  the  result  is  .0342,  which  may  be  written  3.42 
per  cent. 


CALCULATION  OF  OVERRUN  133 

It  is  very  common  for  creamery  patrons  to  test  the  milk 
from  each  of  their  cows,  then  add  the  tests  together  and  divide 
by  the  total  number  of  cows  tested.  The  result  they  will 
call  the  average  test,  and  frequently  such  tests  are  made  usl  of 
as  evidence  against  a  creamery  operator  to  prove  that  his  tests 
at  the  creamery  were  not  correct.  The  fallacy  is  evident  from 
what  has  been  said  above. 

The  same  mistake  is  also  likely  to  be  made  in  finding  the  aver- 
age test  from  several  creamery-plants  and  skimming-stations. 

Calculation  of  Overrun. — The  amount  of  overrun  is  the  dif- 
ference between  the  amount  of  pure  butter-fat  and  the  amount 
of  butter  manufactured  from  that  given  amount  of  fat.  This 
difference,  divided  by  the  amount  of  fat  and  multiplied  by  100 
will  give  the  percentage  of  overrun.  The  calculation  of  the 
overrun  in  the  creamery  should  always  be  made  from  the  fat- 
basis  on  which  the  patrons  are  being  paid.  If  the  fat  is  delivered 
in  the  cream,  the  overrun  should  be  calculated  from  the  fat  in 
the  cream.  The  overrun  calculated  from  the  composition  of  the 
butter  manufactured  would  not  be  an  indication  of  the  correct 
overrun,  as  there  might  be  serious  losses  of  fat  sustained  during 
the  different  steps  in  the  manufacture,  such  as  from  inefficient 
skimming,  incomplete  churning,  and  general  losses  in  the  cream- 
ery. It  is  possible  that  butter  might  show  a  high  content  of  the 
substances  not  fat,  and  yet  not  show  a  good  overrun  on  account 
of  losses;  while  butter  containing  only  a  medium  high  moisture- 
content  might  show  as  great  or  greater  overrun  on  account  of 
thorough  and  efficient  work  during  the  different  steps  of  manu- 
facture. 
The  amount  of  overrun  depends  upon: 

i .  Thoroughness  of  skimming. 

2.  Completeness  of  churning. 

3.  General  losses  in  the  creamery. 

4.  Composition  of  the  butter  manufactured. 

The  theoretical  overrun,  however,  may  be  quite  accurately 
calculated  from  the  composition  of  the  butter  manufactured 
in  a  well-regulated  creamery.  In  creameries  where  the  condi- 
tions of  separation  and  churning  are  almost  perfect,  the  amount 


134  CREAMERY  CALCULATION 

of  fat  lost  in  the  buttermilk  and  the  skim-milk  is  quite  constant 
from  day  to  day,  and  should  not  exceed  .1  per  cent  in  the  skim- 
milk  and  .2  per  cent  in  the  buttermilk,  according  to  the  Babcock 
test.  Basing  the  calculations  upon  the  above  figures,  the  theo- 
retical overrun  may  be  calculated  from  the  composition  of  the 
butter  as  follows : 

If,  for  instance,  we  start  with  iooo  pounds  of  milk  testing 
4  per  cent  fat,  there  will  be  a  total  of  40  pounds  of  fat.  If  we  skim 
32  per  cent  cream  from  4  per  cent  milk,  we  should  have  A,  or  | 
of  it  cream,  and  the  remainder  skim-milk,  or  125  pounds  of 
cream  and  875  pounds  of  skim-milk.  If  there  were  .1  per  cent 
of  fat  in  the  skim-milk,  there  would  be  a  loss  of  .875  pound  of 
fat  during  skimming.  There  would  then  be  39.125  pounds  of  fat 
in  the  125  pounds  of  cream  (40— .875=39.125).  If  10  per  cent  of 
starter  were  added  to  the  cream  we  should  get  137.5  pounds  of 
cream  testing  28.4  per  cent.  (125  pounds  creamXi. 10  =  137.5 
pounds  cream;  39.125^137.5X100  =  28.4  per  cent  fat.)  By 
churning  this  cream  we  should  obtain  about  100  pounds  of  butter- 
milk. If  it  tested  .2  per  cent  fat  there  would  be  a  loss  of  about  .2 
pound  of  fat,  making  a  total  loss  of  fat  in  skim-milk  and  butter- 
milk of  1 .075  pounds.  Subtracting  this  total  loss  of  1 .075  from  40 
pounds  we  would  have  38.925  pounds  of  fat  left  to  be  made  into 
butter  (40  —  1.075=38.925  pounds  of  fat).  If  the  butter  on 
analysis  proves  to  contain  82  per  cent  fat,  the  total  number  of 
pounds  manufactured  will  be  38.925  -5-  .82  =47.47  pounds  of  butter. 
47.47—40  =  7.47  pounds  theoretical  overrrun,  and  7.47^40X100 
=  18.7  per  cent  overrun  (theoretical). 

It  is  evident  that  the  losses  of  fat  will  vary  according  to  the 
different  conditions.  The  richer  the  cream,  and  the  less  fat  in 
the  whole  milk  to  be  skimmed,  the  more  skim-milk  there  will  be; 
the  thinner  the  cream  and  the  more  fat  there  is  in  the  milk  to  be 
skimmed,  the  less  skim-milk  there  will  be,  and  consequently 
with  the  same  skimming  efficiency  less  fat  will  be  lost  in  the  skim- 
milk.  The  thinner  the  cream  is  the  more  buttermilk  there  will 
be.  These  conditions  must  be  left  for  the  operator  to  govern 
according  to  the  conditions  present. 

The  actual  amount  and  per  cent  of  overrun  as  determined 


WHAT  SHOULD  THE  OVERRUN  OF  CREAMERY  BE?    135 

in  creameries  is  calculated  as  described  previously.     The  formula 
is  as  follows : 


Butter  — fat 

— X 1 00  =  per  cent  of  actual  overrun. 

Calculation  of  Churn-yield. — Instead  of  expressing  the 
increase  of  butter  over  that  of  fat  in  the  percentage  overrun, 
as  above,  it  is  often  customary  among  creamer ymen  to  speak 
of  the  "  churn-yield.' '  For  instance,  they  say  that  their  test  was 
3.90,  and  their  churn-yield  was  5,  meaning  that  on  the  average 
each  100  pounds  of  milk  contained  3.9  pounds  of  fat  and  yielded 
5  pounds  of  butter.  The  churn-yield  is  always  expressed  in  per- 
centage, and  is  obtained  by  dividing  the  total  pounds  of  butter 
obtained  by  the  total  pounds  of  milk  from  which  the  butter  was 
made,  according  to  the  following  formula: 

Pounds  of  butter 

— T" — 7 — 77T-  X 100  =  churn-yield. 

Pounds  of  milk  J 

In  case  cream  is  handled  instead  of  milk,  the  same  may  be 
obtained  by  substituting  "  pounds  of  cream  "  for  "  pounds  of 
milk  "  in  the  formula. 

What  Should  the  Overrun  in  a  Creamery  Be? — In  discussing 
this  problem  we  shall  take  80  per  cent  as  the  legal  standard  for 
fat  in  butter.  If  every  churning  of  butter  were  to  drop  to  this 
standard,  but  none  below  it — a  thing  quite  impossible  of  attain- 
ment— if  the  patrons  were  credited  with  all  the  fat  the  creamery 
received,  and  if  there  were  no  mechanical  losses,  and  no  fat  in  the 
buttermilk,  then  every  80  pounds  of  milk-fat  received  would 
make  100  pounds  of  butter;  that  is,  100  pounds  of  fat  would 
make  125  pounds  of  butter,  or,  the  overrun  would  be  25  per  cent. 

The  creamery  has  some  gains  and  some  losses  which  tend  to 
offset  each  other. 

The  gains  come  mainly  from  two  sources,  namely,  (1)  a  small 
fraction  of  a  pound  of  cream  on  some,  but  not  all,  of  the  cans  of 
cream.  (2)  A  small  fraction  of  a  per  cent  of  fat  on  some,  but  not 
all,  of  the  cream  tested. 


136  CREAMERY  CALCULATION 

In  weighing  cream  half-pounds  should  be  credited,  and  in  the 
Babcock  test  of  the  cream  readings  should  be  made  by  half  and 
not  whole  per  cents,  thus  30.0  per  cent,  30.5  per  cent,  31.0  per 
cent,  etc.,  and  not  30.0  per  cent,  31.0  per  cent,  etc. 

Following  out  this  principle,  the  average  gain  in  weight, 
per  can  of  cream,  will  not  exceed  a  quarter  of  a  pound,  and  the 
average  gain  in  per  cent  of  fat  will  not  exceed  0.25  per  cent. 

The  losses  may  be  enumerated  as  follows : 

(1 )  The  Loss  of  Fat  in  the  Buttermilk.^ -This  will,  under  present 
conditions,  easily  equal  0.5  per  cent.  Our  extensive  investigation 
of  the  losses  of  fat  in  buttermilk,  including  complete  records  of 
several  hundred  churnings  in  different  creameries,  shows  this  to 
be  a  very  conservative  estimate ;  and  tests  of  hundreds  of  samples 
of  buttermilk  in  the  laboratory  of  the  American  Association  of 
Creamery  Butter  Manufacturers  fully  support  this  estimate. 

(2)  Losses  in  Packing. — Enough  butter  must  be  put  into  a 
package  to  insure  its  having  the  proper  weight  when  it  reaches 
the  market. 

(3)  Mechanical  losses,  due  to  cream  adhering,  to  a  small 
extent,  to  the  different  utensils — cans,  vats,  etc.  Under  this 
head  may  be  included  the  occasional  spilling  of  small  quantities 
of  cream. 

(4)  If  practically  all  of  the  butter  is  to  come  up  to  the  standard 
of  80  per  cent  fat,  the  average  per  cent  of  fat  in  the  butter  will 
exceed  this  a  little. 

(5)  If  the  results  of  the  investigation  made  by  Siegmund 
and  Craig,  are  to  be  accepted  as  correct,  the  Babcock  test  of 
cream,  as  ordinarily  conducted,  gives  a  reading  that  is  a  little 
high.  Their  findings  are  summarized  in  the  chapter  on  "  Receiv- 
ing, Sampling,  Grading  and  Testing. " 

As  a  basis  for  estimating  what  the  overrun  in  a  well-con- 
ducted creamery  should  be,  an  8-gallon  can  of  cream  will  be  taken 
as  an  average  shipment  and  it  will  be  assumed  that  the  creamery, 
in  weighing  and  testing  the  cream,  credits  the  patron  with  65.0 
pounds  of  cream  testing  30.0  per  cent,  whereas  the  actual  weight 
of  the  cream  is  65.25  pounds,  and  the  actual  test  of  the  cream  is 
30.25  per  cent.     It  will  also  be  assumed  that  in  a  tub  of  butter 


=  ig. 

50 

lbs^ 

=  i9 

•738 

=  45 

•5 

m 

.227 

lb. 

=  19. 

511 

lbs. 

CALCULATION  OF  DIVIDENDS  137 

marked  62  pounds,  net,  there  are  actually  62.5  pounds  of  butter 
to  allow  for  shrinkage. 

Amount  of  fat  credited  to  patron,  30  per  cent  of  65  lbs. 

Actual  amount  of  fat  in  cream,  30.25  per  cent  of  65.25  lbs. 

Weight  of  buttermilk,  70  per  cent  of  65  lbs. 

Per  cent  of  fat  in  buttermilk,  0.5  per  cent 

Weight  of  fat  in  buttermilk,  0.5  per  cent  of  45.5  lbs. 

Weight  of  fat  in  butter,  19.738— .227 

100 
Weight  of  butter  made,  on  basis  of  80  per  cent  fat,  — —  X  19.511  =  24.39 

80 

62 

Weight  of  butter  sold,  X  24 .  39  =  24 .  2 

62.5 

24.2-19.5^ 

Overrun Xioo  =24.1% 

19-5 

In  the  above  calculation  no  account  has  been  taken  either  of 
the  mechanical  losses  or  of  the  fact  that  the  average  per  cent  of 
fat  in  the  butter  will,  of  necessity,  slightly  exceed  the  minimum 
standard  of  80  per  cent. 

In  conclusion,  then,  we  would  say  that  while  the  overrun 
may,  and  will,  vary  to  some  extent,  from  day  to  day  and  from 
week  to  week,  the  creamery  that  does  careful  weighing  and  test- 
ing, and  credits  its  patrons  with  half-pounds  of  cream  and  half 
per  cents  of  fat,  will  be  likely  to  have  an  overrun  for  the  year  of 
about  23  to  24  per  cent.  If  it  has  this  it  is  doing  careful,  efficient 
work.  On  the  other  hand,  if  the  overrun  is  much  above  or  below 
this  something  is  wrong  somewhere  and  needs  to  be  remedied. 

Calculation  of  Dividends. — The  method  of  calculating  divi- 
dends will  vary  according  to  the  agreements  between  the  manu- 
facturer of  the  butter  and  the  milk  and  cream  producers.  Some 
manufacturers  agree  to  make  the  butter  for  so  many  cents  per 
pound  of  butter  (usually  3  or  4  cents).  Occasionally  the  cream- 
ery proprietor  agrees  to  pay  a  final  fixed  sum  for  milk  delivered 
containing  a  definite  amount  of  fat  (usually  4  per  cent).  These 
two  methods  are  not  in  use  much  at  the  present  time,  although  in 
the  eastern  part  of  the  United  States  the  method  of  paying  the 
operator  so  much  per  pound  of  butter-fat  manufactured  is  quite 
common. 

The  two  methods  most  commonly  used,  especially  in  the 
central  West,  are  as  follows: 


138  CREAMERY  CALCULATION 

(i)  Pay  so  much  per  pound  of  butter-fat  based  upon  some 
standard  market  price,  such  as  Chicago  or  New  York.  The 
amount  paid  now  by  the  central  plants  for  butter-fat  is  usually 
2  or  3  cents  per  pound  below  "  New  York  Extras,"  and  the  com- 
pany pays  all  freight  or  express  charges. 

(2)  Pay  per  pound  of  fat  based  upon  the  net  income  of  the 
creamery. 

1.  The  former  method  of  paying  for  butter-fat  has  become 
quite  common.  Nearly  all  the  hand-separator  or  central  plants 
are  paying  for  butter  according  to  this  method.  Payments  are 
usually  made  at  each  delivery  or  every  two  weeks.  Although 
this  causes  more  work,  it  is  much  more  satisfactory  to  the  patrons 
than  to  pay  oruValf^e  end  of  each  month. 

In  order  to  calculate  dividends  when  paid  at  the  end  of  two 
weeks  or  at  the  end  of  each  month,  the  first  step  is  to  find  how 
many  pounds  of  butter-fat  have  been  delivered  by  each  patron. 
If  composite  samples  are  taken,  and  these  tested  for  fat  at  inter- 
vals of  one  week,  which  would  make  about  four  tests  during  the 
month,  and  two  during  half  a  month,  the  results  of  the  several 
tests  may  be  added,  and  the  sum  divided  by  the  number  of  sam- 
ples tested.  This  may  give  the  average  test,  but  it  must  be  borne 
in  mind  that  this  method  is  also  likely  to  give  wrong  results. 
Especially  is  this  so  when  cream  is  delivered  which  varies  in 
quantity  as  well  as  quality  during  the  different  parts  of  the  month. 

If  cream  only  is  being  received,  it  is  a  good  plan  to  test  each 
patron's  cream  every  day,  as  it  is  more  or  less  difficult  to  get 
absolutely  accurate  composite  samples  from  creams  of  different 
richness.  Besides  this,  the  patrons  can  get  the  test  as  well  as 
the  weight  of  the  cream  of  each  previous  day's  delivery,  and  thus 
know  how  their  account  stands  from  day  to  day.  A  little  more 
labor  is  involved  in  doing  this,  but  in  the  long  run  it  keeps  the 
patrons  better  satisfied. 

2.  If  the  price  of  butter-fat  per  pound  is  being  based  upon  the 
net  income,  as  is  the  case  in  nearly  all  co-operative  creameries, 
and  also  in  many  proprietary  creameries,  the  first  step  is  to  find 
out  how  much  butter-fat  each  patron  delivered  during  the  spe- 
cified time, — two  weeks  or  a  month,  whichever  may  be  the  case. 


CALCULATION  OF  DIVIDENDS 


139 


140  CREAMERY  CALCULATION 

When  this  has  been  obtained,  the  total  pounds  of  fat  delivered  by 
all  the  patrons  are  found.  From  the  gross  income  the  total 
expenses  of  running  the  creamery  are  subtracted.  The  remainder 
represents  the  net  income.  This  is  then  divided  by  the  total 
pounds  of  fat  delivered  to  the  creamery,  and  the  quotient  repre- 
sents the  price  per  pound  of  butter-fat  to  the  patrons. 

Knowing  the  price  to  be  paid  to  the  patrons  for  i  pound  of  fat, 
the  sum  due  to  each  patron  is  found  by  multiplying  the  price  per 
pound  by  the  total  number  of  pounds  of  fat  each  patron  delivered 
during  the  specified  time. 

In  some  instances  provisions  are  made  for  a  "  sinking  fund." 
This  is  a  name  given  to  a  fund  raised  by  deducting  so  much  per 
pound  of  fat,  or  per  ioo  pounds  of  milk,  from  each  patron's 
delivery  at  the  end  of  each  month.  This  fund  is  for  the  pur- 
pose of  paying  off  a  debt  gradually,  or  for  raising  a  fund  for 
new  equipment,  or  other  improvements  in  the  creamery.  In 
case  such  money  is  to  be  withheld,  it  is  deducted  previous  to 
making  the  final  calculation. 

Cream-raising  Coefficient. — By  the  term  cream-raising  coeffi- 
cient we  understand  the  percentage  of  the  fat  removed  from  the 
milk  during  the  process  of  separation.  The  calculation  of  the 
cream-raising  coefficient  may  be  illustrated  as  follows: 

Suppose  we  have  ioo  pounds  of  milk  containing  4  per  cent  fat, 
and  yielding  85  pounds  of  skim-milk  and  15  pounds  of  cream, 
the  skim-milk  containing  .2  per  cent  fat. 

Total  fat  in  whole  milk  =  100  lbs.  X  4  per  cent=  4  lbs. 
Total  fat  in  skim-milk  =  85  lbs.  X.2  per  cent  =  .17  lb. 
Total  fat  in  cream  =     4  lbs.  — .17  lb.  =3.83  lbs. 

3.83X100 

=  95-75  Per  cent  01  the  total  4  pounds  of  fat,  or  the 

cream  raising  coefficient. 

Statement  to  Patrons. — A  complete  statement  should  be 
made  at  the  time  of  each  settlement  and  should  be  accompanied 
by  the  check.  A  statement  similar  to  the  following  one  may 
serve  as  an  example:1 

1  Creamery  Butter-making  by  Michels. 


STATEMENT  OF  PATRONS  141 
CREAMERY   COMPANY 


Mr 

For  the  month  of- 


IN   ACCOUNT   WITH 


192- 


No.  pounds  milk  delivered 

by  you 

Average  test 

No.  pounds  butter-fat    . 
Price  per  pound    .      .      .      .  $ . 


Cr. 


Pounds  butter  at  ... 

Cans,  at 

Cash 

Hauling  at. . .  .        per  100  lbs 

$ 


Dr. 


Balance  due  you 

Total  pounds  milk  delivered  at  creamery 
Average  test  at  creamery       .... 
Total  pounds  butter-fat  at  creamery 

lbs.  at 


Sales  of  butter 


Less- 


-cts.  for  making. 


Balance  due  patrons 
Per  cent  overrun    . 
Testing  witnessed  by. 


S 
I 

s 
S 

s 


Prcst. 

.Secy. 


At  the  end  of  the  year  a  final  statement   should  be  made 
by  the  respective  officers,  similar  to  the  following  one: 


ANNUAL   REPORT 

Incorporated 192 ....         Commenced  Operations 192 . 

Annual  Report,  192 .... 

of  the 

—CREAMERY  COMPANY 

of , . ,  Iowa. 

( Butter-maker; Asst.  Butter-maker 

Capital  Stock,  $ Paid  in  $ 

officers  and  directors. 
President,         Secretary,  Treasurer, 


142 


CREAMERY  CALCULATION 


SECRETARY'S  REPORT 

To  the  Stockholders:    Your  Secretary  herewith  submits  the  following  report 
for  the  year  ending  December  31,  192.  . . . 

Total  pounds  of  milk  received 

Total  pounds  butter-fat  contained  in  same  .... 

Total  pounds  butter  manufactured 

Average  test  of  butter-fat  per  hundred  pounds  of  milk 
Average  yield  of  butter  per  hundred  pounds  of  milk  . 
Average  price  paid  per  hundred  pounds  of  milk 
Average  price  paid  per  hundred  pounds  of  butter-fat  . 
Average  per  cent  increase  of  churn  over  test  (overrun) 
Average  price  received  per  pound  of  butter  .... 
Average  monthly  expenses  of  running  creamery 
Average  cost  of  manufacturing  butter  per  pound    . 


Following  is  a  Monthly  Statement  for  the  year  192. 

January 
February 
March 
April  . 
May   . 
June   . 
July    . 
August 
September 
October    . 
November 
December 

Totals 


TREASURER'S   REPORT. 


To    the    Stockholders    of    the. 


-Creamery    Company:    Your 


Treasurer  herewith  submits  the  following  report : 

Statement  of  Cash  Received  and  Disbursed. 
Receipts  Disbursements 

Total       Total     

Respectfully  submitted, ,  Treasurer. 

Cashier  of  Bank. 


PAYING  FOR  FAT  IN  CREAM  143 

STATEMENT  OF  CASH   RECEIVED  AND   DISBURSED 

Receipts.  Disbursements. 

Received  for  butter   .      .      .  $ Paid  to  patrons  for  milk  .      .  $ 

Running  expenses  of  cream- 
ery and  supplies  on  hand 

Paid    for    machinery,    ma- 
terial,  repairs,    etc.    (out 

of  percentage  fund)     

Paid  dividend  on  stock  for 
i 9 2.. (out   of    percentage 

fund)      

Paid  dividend  on  stock  for 
192.  (out    of    percentage 

fund)     .      .      .      .      

Total    amount    of    cash    re-  Total     amount     of     orders 

ceived  and  paid  to  Treas-  drawn  on  Treasurer     

urer        Cash   balance   in   hands   of 

Cash    balance    in    hands    of  Treasurer,  Jan.  192 

Treasurer,  Jan.  192 

Total Total       ,      ,      ,     

REPORT  OF  AUDITING  COMMITTEE. 

To  the  Stockholders  of  the Creamery  Company: 

We,  the  undersigned,  appointed  by  your  Board  of  Directors  to  examine  and 

audit  the  Books,  Accounts,  and  Vouchers  of  the  Secretary  and  Treasurer  of  the 
Creamery  Company  for  the  year  192.  .,  hereby  certify  that  we 

have  carefully  examined  the  same  and  compared  them  with  the  above  reports  of 

said  officers,  and  find  them  correct. 

In  witness  whereof  we  have  hereunto  set  our  hands  at  ,  Iowa 

this.  .  .  .day  of a.d.,  192 


Auditing  Committee. 


Paying  for  Fat  in  Cream  Compared  with  Paying  for  Fat  in 
Milk. — It  is  evident  that  when  patrons  deliver  fat  in  the  form 
of  milk  the  creamery  operator  sustains  a  loss  in  the  skim-milk, 
while  if  the  fat  is  delivered  in  the  form  of  cream,  no  fat  is  lost  in 
the  skim-milk  at  the  creamery,  and  consequently  the  cream  patron 
should  receive  more  per  pound  of  fat  delivered  than  the  whole- 
milk  patron  provided  the  quality  of  the  fat  in  the  cream  is  as 
good  as  that  in  the  form  of  milk.  The  butter-maker  sliould 
obtain  a  larger  overrun  from  the  fat  of  the  cream  than  he  does 
from  the  fat  of  the  milk.     The  amount  which  the  patrons  should 


144  CREAMERY  CALCULATION 

be  paid  for  fat,  delivered  in  the  form  of  cream,  depends  upon  the 
thoroughness  of  skimming.  If  iooo  pounds  of  milk  testing 
4  per  cent  fat  were  bought  and  skimmed,  there  would  be  a  loss 
of  about  .9  of  a  pound  of  fat  during  the  skimming,  which  would 
make  about  1  pound  of  butter,  worth  about  30  cents.  If  bought 
in  the  form  of  cream  this  loss  would  not  be  sustained.  The 
above  loss  during  skimming,  according  to  the  figures  mentioned, 
would  amount  to  about  three-quarters  of  a  cent  per  pound  of 
butter  manufactured.  The  fat  lost  during  the  skimming  process 
would  amount  to  about  2  per  cent  of  the  total  fat.  If  the  cream 
fat  be  increased  by  2  per  cent,  an  approximate  basis  for  paying 
milk  and  cream  patrons  is  obtained. 

This  argument,  however,  will  hold  good  only  when  the  cream 
is  graded  and  paid  for  on  a  strictly  quality  basis.  This  is  decid- 
edly the  exception,  not  the  rule,  at  the  present  time.  Milk, 
however,  is  graded  to  a  much  larger  extent.  If  it  is  seriously 
off  in  flavor  it  is  likely  to  be  rejected;  furthermore,  it  has  to  be 
cooled  promptly  to  prevent  it  from  souring,  and  this  holds  fer- 
mentations in  check.  Everything  considered,  we  are  quite 
inclined  to  the  view  that  the  cream  and  milk  patrons  of  a  creamery 
should — under  present  conditions  at  least — be  placed  on  a  par 
as  to  the  price  paid  them  per  pound  of  fat. 


CHAPTER  XI 
HEATING  MILK  PREVIOUS  TO  SKIMMING 

Reasons  for  Heating. — Owing  to  the  fact  that  all  separators 
will  skim  closer  and  not  clog  so  easily  when  milk  is  heated,  nearly 
all  creameries  heat  or  warm  the  milk  previous  to  skimming. 
When  the  milk  is  thus  heated  and  stirred  in  a  pure  atmosphere, 
many  undesirable  odors  or  taints  escape.  With  an  increase  of 
temperature,  the  viscosity  of  the  milk  is  lessened,  due  chiefly  to 
the  softening  and  separation  of  the  fat-globules.  Such  an 
increased  fluidity  of  the  milk  lessens  the  resistant  force  of  the 
fat-globules  when  exposed  to  the  centrifugal  force  of  the  sepa- 
rator. The  higher  the  temperature  the  more  fluid  the  milk 
becomes,  and  consequently  the  more  easily  the  fat  can  be  sep- 
arated. 

By  warming  the  milk  to  a  high  temperature  and  leaving  it  for 
some  time,  then  cooling  quickly  again  to  skimming  temperature 
(oo°  F.)  and  separating,  the  skimming  efficiency  of  the  separator 
is  increased  materially.  If  the  milk  has  been  standing  at  a  very 
low  temperature  for  at  least  three  hours,  and  then  is  quickly 
warmed  up  to  the  usual  skimming  temperature,  and  skimmed, 
the  warming  of  the  milk  has  comparatively  little  effect  in  bringing 
it  into  a  good  condition  for  skimming.  It  will  thus  be  seen  that 
it  is  possible  to  skim  milk  at  the  same  temperature,  and  yet  get 
different  results,  due  to  previous  temperature  conditions.  Dura- 
tion of  temperature  should  be  considered  as  well  as  the  tempera- 
ture itself. 

The  temperature  to  which  milk  should  be  heated  previous 
to  skimming  varies  according  to  different  investigators.  The 
temperature  mostly  employed  in  the  past  in  this  country,  and 
perhaps  at  the  present  time,  is  about  90  °  F.     This  comparatively 

145 


146  HEATING  MILK  PREVIOUS  TO  SKIMMING 

low  temperature  was  fixed  owing  to  the  supposedly  bad  effect 
high  skimming  temperatures  had  upon  the  body  of  the  finished 
butter.  Exposing  milk  at  high  temperatures  to  the  centrifugal 
force  in  a  separator  was  said  to  produce  a  greasy  body  in  butter. 
According  to  experiments  conducted  at  the  Iowa  Experiment 
Station  by  the  authors,  milk  can  be  skimmed  at  1750  F.  without 
any  injury  to  the  quality  of  the  butter,  providing  the  cream 
is  cooled  to  ripening  temperature,  or  below,  as  soon  as  it  has 
been  skimmed.  After  the  ripening  has  been  completed  the 
cream  should  be  exposed  at  least  three  hours  to  a  low  tempera- 
ture (500  F.)  previous  to  churning. 

If  the  milk  is  heated  in  any  of  the  best  modern  heaters,  there 
will  be  no  injurious  results  to  the  quality  of  the  butter.  Pro- 
fessor Dean,  at  the  Ontario  Agricultural  College,  has  also  found 
it  practical  to  heat  to  pasteurization  temperature  previous  to 
skimming.  In  many  creameries  in  Denmark  this  method  of 
heating  milk  is  also  followed.  The  Danes,  as  a  rule,  however, 
pass  the  heated  milk  over  a  cooler  before  it  goes  into  the  sep- 
arator. 

The  chief  difficulty  encountered  by  the  authors  in  heating 
milk  to  such  a  high  temperature  previous  to  skimming  was 
that  the  upper  bearing  in  the  separator  got  so  hot  that  it  was 
deemed  injurious  to  the  separator,  although  the  bearing  did 
not  heat  to  such  an  extent  as  to  cause  the  running  of  the  machine 
to  be  abnormal  in  any  way. 

Advantages  of  Warming  Milk  to  High  Temperature  Previous 
to  Skimming. — The  advantages  of  heating  milk  to  a  high  tem- 
perature (175°  F.)  previous  to  skimming  may  be  summarized  as 
follows: 

(1)  Undesirable  taints  are  eliminated  from  the  milk  to  a 
greater  extent  than  can  be  accomplished  in  any  other  way, 
without  applying  chemicals. 

(2)  The  heating  of  whole  milk  destroys  the  germs  in  the 
resultant  skim-milk  and  cream  practically  as  efficiently  as  when 
they  are  heated  after  the  skimming  process  has  been  completed. 

(3)  Less  heating  and  cooling  apparatus  is  necessary. 

(4)  Closer  skimming  is  possible. 


HOW  HEATED  147 

How  Heated. — There  are  two  methods  by  which  milk  is 
heated  previous  to  skimming.  First,  by  the  use  of  direct  live 
steam;  second,  by  the  use  of  heaters  which  heat  with  steam  or 
hot  water  indirectly. 

Heating  of  milk  with  direct  live  steam  is  accomplished  in 
two  ways:  first,  by  entering  a  steam  hose  into  the  vat  full  of 
milk;  and,  second,  by  making  use  of  special  heaters,  which  allow 
steam  to  come  in  direct  contact  with  the  milk  as  the  milk  passes 
through. 

The  method  of  heating  milk  with  direct  live  steam  cannot 
be  too  strongly  condemned,  because  it  has  a  bad  effect  upon 
the  flavor  of  the  butter.     At  the  Milwaukee  National  Butter 


Fig.  44. — The  Twentieth-century  milk-heater. 


contest  in  1903,  where  over  eight  hundred  exhibitors  were 
represented,  the  authors  noticed  that  where  the  criticism 
"  burnt,"  "oily  flavor  "  was  made  on  the  score  card,  the  milk 
from  which  the  butter  was  made  had  in  most  cases  been  heated 
with  live  steam.  The  burnt  flavor  may  possibly  be  due  to  the 
sudden  excessive  heat  to  which  the  milk  will  be  exposed  when 
coming  in  contact  with  live  steam.  The  greatest  danger, 
however,  in  heating  milk  with  live  steam  is,  that  impurities 
from  the  pipes  and  boiler  are  likely  to  be  transmitted  to  the 
milk,  and  cause  bad  flavors.  In  most  of  the  creameries  the 
exhaust-steam  from  the  engine  is  used  to  heat  the  water  for  the 
boiler.  This  steam  is  likely  to  carry  with  it  cylinder-oil,  which 
will  impart  undesirable  flavors  to  the  butter.  Some  creameries 
are  also  using  boiler  compounds  for  the  removal  of  scales.     These, 


148  HEATING  MILK  PREVIOUS  TO  SKIMMING 

when  subjected  to  high  heat  and  pressure,  are  likely  to  be 
transmitted  to  the  steam-pipes,  and  from  there  with  the  steam 
into  the  milk.  The  scale  and  rust  of  steam-pipes  are  also  likely 
to  be  transferred  to  the  milk. 

The  right  way  to  heat  milk  previous  to  skimming  is  to  make 
use  of  one  of  the  special  heaters  on  the  market,  which  heat  by 
the  use  of  steam  or  hot  water  indirectly. 


CHAPTER  XII 
SEPARATION  OF  CREAM 

In  the  process  of  the  manufacture  of  butter  it  is  essential 
that  the  fat  of  the  milk  shall  be  concentrated  into  a  compara- 
tively small  portion  of  the  milk  serum.  This  concentration  of 
fat  carries  with  it  a  portion  of  all  the  other  milk  constituents,  and 
the  product  is  called  cream.  It  is  possible  to  churn  milk  with- 
out any  separation,  but  a  much  greater  loss  is  attendant,  if  the 
fat  is  not  brought  together  by  the  process  called  separation. 

The  different  kinds  of  cream  may  be  classified  according  to 
the  different  methods  of  cream-separating: 

Shallow-pan  cream. 
Gravity  cream .  . .   -j  Deep-setting  cream. 


Cream 


Centrifugal  cream 


Water  dilution  cream  (hydraulic). 

Hand-separator  cream. 
Creamery-separator  cream. 


GRAVITY  CREAMING 

Shallow-pan  System. — This  method  of  creaming  is  used 
mostly  on  farms  which  are  situated  unfavorably  in  relation  to  a 
creamery,  or  for  some  other  reasons  do  not  send  their  milk  to 
the  creamery.  It  consists  in  placing  the  milk  in  shallow  pans, 
from  2  to  4  inches  in  depth,  as  soon  after  milking  as  possible. 
The  milk  is  then  placed  where  it  can  be  quickly  cooled  to  a 
temperature  of  at  least  6o°  F.  A  lower  temperature  than  this 
is  desirable  if  conditions  permit.  The  atmosphere  in  the  room 
in  which  the  milk  is  standing  must  be  pure,  free  from  dust, 
draught,  and  any  undesirable  taints  or  odors,  since  it  takes 
about  thirty-six  hours  of  quiet  standing  for  the  cream  to  rise. 
If  there  is  a  constant  current  of  air  in  the  room,  a  leathery 

149 


150  SEPARATION  OF   CREAM 

cream  is  likely  to  form.  At  the  end  of  this  time  the  cream  is 
removed  by  the  use  of  a  skimmer,  made  especially  for  this  pur- 
pose. It  is  difficult,  however,  to  remove  all  the  cream  by  this 
means.  The  perforated  skimmer  should  never  be  used.  It 
allows  the  thin  under-layer  of  cream  to  run  through  and  be  lost 
in  the  skim-milk. 

If  the  conditions  are  such  that  cool  water  can  be  constantly 
circulated  around  the  pans  containing  the  milk,  the  temperature 
can  easily  be  made  to  go  below  6o°  F.,  and  the  creaming  process 
is  facilitated.  When  such  conditions  are  present,  the  depth  of  the 
milk  in  the  pans  can  safely  be  increased  to  about  6  inches.     Under 

the  most  favorable  conditions  about 
.5  per  cent  fat  will  remain  in  the  skim- 
milk. 

Deep-setting  System. — This  system 
is  undoubtedly  the  best  method  of 
gravity  creaming.  When  it  is  properly 
carried  on  the  fat  can  be  removed  so 
completely  that  no  more  than  .2  per  cent 
of  fat  remains  in  the  skim-milk.  It  con- 
FiG.45.-Cooley  creamer  '  gists  of  putting  m[\k  [nto  deep  cans 
and  elevator.  7      ..  r  „  . 

(ordinary  four-gallon  shotgun  cans  are 

usually  employed)  immediately  after  the  milk  has  been  drawn 
from  the  cow.  Then  it  is  put  into  cold  water,  and  generally 
cooled  down  to,  and  maintained  at,  a  temperature  of  about 
550  F.  The  cream  will  rise  in  about  twenty-four  hours.  Better 
results  can  be  obtained  if  the  water  is  cooled  down  to  about  40 ° 
with  the  use  of  ice. 

One  reason  why  this  system  is  so  much  in  use,  even  in  cream- 
ery localities,  is  that  the  cream  obtained  is  nearly  always  of  a 
good  quality.  The  farmer  knows  that  unless  the  milk  be  cooled 
quickly,  and  maintained  at  a  low  temperature,  the  cream  will  not 
rise  freely.  For  this  reason  the  milk  is  systematically  and  thor- 
oughly cooled,  which  is  one  of  the  great  essentials  in  checking  the 
growth  of  the  ferments  in  milk  and  keeping  the  milk  in  good  con- 
dition. In  many  parts  of  the  eastern  United  States,  the  deep- 
getting  system  is  in  general  use.     A  special  form  of  can  is  used, 


GRAVITY   CREAMING  151 

it  is  simply  an  ordinary  four-gallon  can,  about  8  inches  in  diameter 
and  20  inches  deep.  It  has  a  glass  on  one  side  near  the  bottom  or 
near  the  top,  which  allows  the  reading  of  the  thickness  ofthe 
layer  of  cream.  On  each  side  of  the  glass  is  a  graduated  scale, 
which  gives  the  reading  in  inches.  In  case  the  cream  is  being 
sold  to  a  creamery,  the  hauler  comes  along,  notes  the  depth  of  the 
layer  of  cream,  and  records  the  number  of  inches  of  cream  oppo- 
site the  patron's  name.  At  the  end  of  the  month,  or  whenever 
the  time  for  payment  comes,  the  money  is  apportioned  according 
to  the  number  of  inches  of  cream  delivered  by  each  of  the  patrons. 
No  test  for  fat  is  made.  This  is  what  is  known  as  the  "  Cooley 
system,"  and  is  used  quite  extensively  in  the  East,  especially  in 
Massachusetts. 

While  cream  usually  arrives  at  the  creamery  in  a  fair  condition, 
there  is  the  objection  that  the  cream  is  always  thin.  It  seldom 
contains  any  more  than  18  or  20  per  cent  of  fat. 

No  good  explanation  has  yet  been  given  why  cream  in  a  deep 
layer  of  milk  at  400  F.  should  rise  more  quickly  and  more  com- 
pletely than  in  a  thin  layer  at  a  higher  temperature.  Arnold  l 
seeks  to  explain  it  by  saying:  "  Water  is  a  better  conductor  of 
heat  than  fat;  hence  when  the  temperature  of  the  milk  varies 
either  up  or  down,  the  water  in  the  milk  feels  the  effect  of  the 
heat  or  cold  sooner  than  the  fat  in  the  cream  does.  Therefore 
the  cream  is  always  a  little  behind  the  water  in  swelling  with  heat 
or  shrinking  with  cold,  thus  diminishing  the  difference  between 
the  specific  gravity  of  the  milk  and  cream  when  the  temperature 
is  rising,  and  increasing  it  when  the  temperature  is  falling." 

This  explanation  is,  according  to  Babcock,2  not  satisfactory. 
He  says:  "  Though  it  is  true  that  water  is  a  better  conductor 
of  heat  than  fat,  the  small  size  of  the  fat-globules  renders  it 
impossible  that  under  any  circumstances  there  can  be  more  than  a 
small  fraction  of  a  degree  of  difference  between  the  temperature 
of  the  fat  and  that  of  the  milk  serum.  Moreover,  with  the  limits 
of  temperature  practical  for  a  creamery,  (900  to  400  F.),  the 
coefficient  of  expansion  of  butter-fat  is  more  than  three  times  as 

1  American  Dairying,  p.  210. 

2  Wisconsin  Experiment  Station,  Bull.  18,  p.  24. 


152  SEPARATION  OF  CREAM 

great  as  that  of  water,  so  that  in  order  to  maintain  the  same  rela- 
tive difference  in  their  specific  gravities  when  the  temperature  is 
falling,  the  milk  serum  must  cool  nearly  three  times  as  quickly 
as  the  fat.  In  other  words,  when  the  milk  serum  has  cooled  from 
oo°  to  400,  or  500  F.,  the  fat-globules  should  have  lost  less  than 
1 70,  and  should  still  have  a  temperature  of  over  700  F.,  a  differ- 
ence between  the  temperature  of  milk  serum  and  fat  of  more 
than  33  °.  Such  a  condition  is  manifestly  impossible,  but 
a  less  difference  than  this  would  cause  the  fat  to  become 
relatively  heavier  than  at  first,  and  would  operate  against  the 
creaming. " 

A  low  temperature  increases  the  viscosity  of  the  milk,  and 
consequently  it  would  seem  that  the  resistant  force  of  the  fat- 
globules  in  their  upward  passage  through  the  milk  serum  would 
be  increased,  and  thus  retard  the  creaming.  Babcock  maintains 
that  fibrin  is  partially  precipitated  when  milk  is  allowed  to  stand 
at  a  medium  high  temperature.  The  fibrin,  when  precipitated, 
forms  a  fine  network  of  threads  permeating  the  milk  in  all  direc- 
tions, similar  to  the  network  of  fibrin  in  coagulated  blood.  It  is 
possible  to  conceive  that  such  a  network  would  interfere  with  the 
rising  of  the  fat-globules,  at  comparatively  high  temperatures. 
The  reason  that  fat-globules  will  rise  more  quickly  and  more 
completely  in  the  deep-setting  system  than  in  the  shallow-pan 
system,  might  be  explained  on  this  fibrin  theory  were  it  not  for  the 
fact  that  experiments  conducted  at  the  Cornell  Experiment 
Station  show  that  the  setting  and  cooling  of  milk  may  be  delayed 
long  enough  for  this  fibrin  to  form,  without  any  effect  upon  the 
separation  when  set  and  cooled. 

Probable  Explanation. — There  are  two  factors  which,  taken 
in  conjunction  with  each  other,  seem  to  offer  a  reasonable 
explanation  of  the  efficiency  of  the  deep-setting  system. 

The  first  of  these  is  that  cooling  the  milk  to,  and  holding 
it  at,  a  low  temperature  keeps  the  milk  serum  in  a  much  better 
physical  condition.  It  may  not  be  so  fluid  as  it  would  be  at  a 
higher  temperature,  but  there  is  a  minimum  formation  of  fine 
masses  or  particles  of  curdy  matter  that  would  either  imprison 
some  of  the  fat  or  offer  obstruction  to  the  fat-globules,  and 


GRAVITY  CREAMING  153 

clusters  of  globules,  in  rising.  It  is  a  fair  assumption  that  in  the 
experiment  at  the  Cornell  Station  the  milk  was  not  held  long 
enough,  before  cooling,  seriously  to  impair  its  physical  condi- 
tion. 

The  second  very  probable  factor  is  that  of  the  formation  of 
fat  clusters,  through  large  fat-globules  rising  faster  and  coming 
into  contact  with  smaller  ones.  These  and  other  clusters  would 
continue  to  pick  up  isolated  globules  and  smaller  clusters,  and  so 
the  process  would  continue;  clusters  would,  of  course,  rise  more 
readily  than  individual  globules,  and  larger  clusters  would  rise 
more  rapidly  than  smaller  ones.  The  result  would  be  that, 
owing  to  the  good  physical  condition  of  the  milk — the  absence 
of  casein  particles  to  enmesh  the  fat-globules  and  offer  obstruc- 
tion— practically  all  the  fat-globules  would  find  their  way  to  the 
top. 

Water-dilution  Cream  (Hydraulic.) — It  was  thought,  at  one 
time,  that  a  modification  of  the  deep-setting  system,  through 
the  dilution  of  the  milk  with  water  to  the  extent  of  25  per  cent  to 
50  per  cent,  would  greatly  add  to  its  efficiency,  through  reducing 
the  viscosity  of  the  milk.  The  idea  was,  of  course,  commercial- 
ized and  a  number  of  so-called  "  dilution  cream  separators  " 
were  placed  on  the  market.  The  method  is  still  practiced 
to  some  extent,  but  it  is  by  no  means  as  general  as  it  was  at  one 
time. 

While  it  is  true  that  under  very  exceptional  conditions — such 
as  in  setting  the  milk  of  an  occasional  individual  cow  near  the 
end  of  her  lactation  period — some  advantage  may  be  gained,  the 
principle  has  no  general  application.  It  must  be  remembered 
that,  while  the  addition  of  water  to  milk  makes  it  more  liquid,  it 
also  reduces  the  difference  in  specific  gravity  between  the  milk 
serum  and  the  butter-fat,  and  it  is  upon  this  difference  that  we 
depend  to  bring  about  a  separation. 

Even  though  the  skim-milk  should,  at  times,  show  a  lower 
per  cent  of  fat,  this  is  only  an  apparent  advantage,  as  there  is  a 
much  greater  quantity  of  it.  Wing1  obtained  the  following 
results  with  diluted  and  undiluted  milk: 

1  Milk  and  Its  Products,  p.  105. 


154  SEPARATION  OF  CREAM 

Diluted  with  25  per  cent  water,  set  at  6o°  F.  (39  trials),  0.77 
per  cent  fat  in  the  skim-milk. 

Undiluted,  set  at  6o°  F.  (30  trials),  1.00  per  cent  fat  in  the 
skim  milk. 

Undiluted,  set  at  400  F.  (30  trials),  .29  per  cent  fat  in  the 
skim-milk. 

A  test  of  .77  per  cent,  where  the  milk  is  diluted  to  the  extent 
of  25  per  cent,  means  a  greater  loss  of  fat  than  where  the  skim- 
milk  from  undiluted  milk  tests  1.00  per  cent. 

It  will  be  noted  that,  in  his  trials  under  the  dilution  method, 
Wing  set  the  milk  at  6o°.  The  reason  for  this  was  that  advocates 
of  the  system  contended  that  it  would  bring  about  such  a  speedy, 
and  yet  complete,  separation  that  it  was  unnecessary  to* adopt 
low  temperatures.  Wing's  experiments  prove  two  things; 
first,  that  whether  milk  is  diluted  or  undiluted  the  loss  of  fat  is 
heavy  if  the  setting  temperature  is  high,  and,  second,  that  where 
the  milk,  without  dilution,  is  set  at  a  low  temperature  the  cream- 
ing coefficient  is  quite  satisfactory. 

The  valid  objections  to  the  dilution  method  are  as  follows: 

Much  more  bulk  to  handle,  the  use  of  a  larger  number  of  cans, 
and  increased  labor. 

Danger  of  contamination  of  the  milk  and  cream  through  the 
use  of  impure  water. 

Impairment  of  the  value  of  the  skim-milk  for  feeding. 

Injury  to  the  cream  or  butter — the  product  has  an  unde- 
sirable, flattish  flavor. 

The  loss  of  fat  in  the  skim-milk  is  too  great,  as  the  experiments 
by  Wing  show. 

CENTRIFUGAL  CREAMING 

In  the  separation  of  cream  by  centrifugal  machines,  the 
same  principle  is  used  as  in  the  gravity  system  of  separation. 
The  only  difference  is  that  in  the  centrifugal  method  the  force 
which  separates  the  cream  from  the  milk  is  generated  by  artificial 
methods,  and  acts  in  a  horizontal  direction ;  in  the  gravity  system 
the  force  which  separates  the  cream  from  the  milk  is  only  that 
which  results  from  the  difference  in  the  specific  gravity  of  the 


CENTRIFUGAL   CREAMING  155 

cream  and  the  skim-milk,  and  the  force  acts  in  a  vertical  direc- 
tion. The  force  generated  in  the  separator  is  several  thousand 
times  greater  than  the  natural  force  in  the  gravity  method. 
For  this  reason  the  cream  separates  almost  instantaneously  after 
the  milk  has  entered  the  separator  and  is  exposed  to  the  cen- 
trifugal force. 

Advantages. — The  centrifugal  separator  has  several  advan- 
tages over  the  gravity  method,  which  are  apparent  without 
detailed  elaboration.  In  the  first  place,  the  range  of  tempera- 
ture and  condition  of  the  milk  at  which  the  cream  can  be  suc- 
cessfully separated  is  much  greater  than  that  for  successful 
separation  by  the  gravity  method.  Second,  a  much  better 
quality  of  cream  can  be  obtained  by  the  centrifugal  system, 
as  the  separation  can  be  done  before  the  milk  gets  old,  while 
by  the  gravity  method  the  time  required  for  efficient  separation 
is  so  long  that  the  cream  deteriorates  more  or  less  before  it  is 
removed  from  the  milk.  Third,  by  the  centrifugal  method  the 
thickness  of  the  cream  can  be  regulated  to  suit  requirements, 
while  by  the  gravity  method  the  thickest  cream  that  can  be 
obtained  is  about  20  per  cent.  Fourth,  by  the  centrifugal  method 
many  impurities  and  undesirable  germs  are  removed,  while  in 
the  gravity  method  the  exposure  to  open  air,  more  or  less  impure . 
is  likely  to  contaminate  the  milk  with  taints,  and  also  allows  the 
germs  to  fall  into  it.  Fifth,  by  the  centrifugal  method  the  skim- 
milk  is  left  in  a  more  natural  condition.  The  milk  can  be 
skimmed  soon  after  milking,  or  after  it  has  been  delivered  to  the 
creamery,  and  thus  be  in  the  best  possible  condition  for  feeding 
purposes.  Sixth,  the  centrifugal  method  permits  of  a  more 
thorough  separation  of  the  fat.  Butter-fat,  as  a  rule,  is  too 
expensive  to  feed,  when  good  and  much  cheaper  substitutes  can 
be  had. 

History  of  Centrifugal  Separators. — The  first  centrifugal 
separator  was  a  very  simple  one.  It  consisted  of  buckets  hanging 
on  the  ends  of  arms,  or  on  the  periphery  of  a  rotating  horizontal 
flat  wheel  which  swung  on  a  central  axis.  The  milk  was  placed 
in  the  buckets  and  whirled  for  a  time,  and  then  the  machine  (if 
we  may  call  it  such)  was  stopped,  and  the  cream  removed  in  the 


156 


SEPARATION  OF  CREAM 


same  way  as  in  the  gravity  system.  This  method  of  separation, 
according  to  J.  H.  Monrad,1  had  its  origin  in  1864.  As  early  as 
1859  Professor  Fuchs  of  Carlsruhe,  Germany,  suggested  testing 
the  richness  of  milk  by  swinging  tubes  holding  the  samples  of 
milk.  In  1864  Prandtl,  a  brewer  of  Munich,  separated  milk  by 
such  a  device.  In  1870  Rev.  F.  H.  Bond,  of  Northport,  Massa- 
chusetts, worked  out  a  method  of  separation  which  consisted  of 
two  small  glass  jars  attached  to  a  spindle  making  200  revolutions 
per  minute.  By  one  hour's  whirling  the  cream  was  brought  to 
the  top. 

In  1875  Prandtl  exhibited  at  Frankfort-on-the-Main  a  con- 


FiG.  46. — First  centrifugal  separator.     (From  Dairy  Messenger.) 

tinuous  separator,  which  did  not  at  the  time  attract  much  atten- 
tion, due  chiefly  to  the  excessive  amount  of  power  needed  to 
overcome  the  resistant  force  of  the  air.  In  1876  a  Danish  engi- 
neer named  Winstrup  succeeded  in  improving  the  old  bucket 
method.  In  1877  Lefeldt  and  Lentch  offered  for  sale  four  con- 
tinuous separators  with  different  capacities  (from  no  to  600 
pounds  of  milk  per  hour).  During  that  year  also,  the  first 
practical  centrifugal  creamery  was  established  at  Kiel,  Germany. 
In  1877  Houston  and  Thompson  of  Philadelphia  filed  a  patent  for 
the  continuous  method  of  separation  of  cream  from  milk.  The 
patent  was  allowed  in  189 1.     In  March,  1877,  Lefeldt  and  Lentch 

1  Dairy  Messenger,  Oct.,  1892,  p.  109. 


CENTRIFUGAL  CREAMING  157 

invented  a  separator  similar  in  construction  to  the  hollow  bowl — 
a  more  recent  type.  This  machine  did  not  revolve  at  so  rapid  a 
rate  as  our  modern  machines  do,  nor  did  it  have  arrangements  for 
continuous  inflow  and  discharge.  It  was  intermittent  in  its 
work,  and  it  was  necessary  to  stop  at  intervals  to  remove  the 
cream  and  skim-milk.  The  year  1879  marked  the  greatest 
advancement  toward  the  perfection  of  modern  separators,  in  the 
appearance  of  the  Danish  Weston,  invented  in  Denmark,  and 
the  De  Laval,  invented  in  Sweden  during  that  year.  This  led 
to  continuous  milk  and  cream  discharges,  and  consequently  also 
to  the  continuous  inflow  of  whole  milk.  These  machines  were 
of  the  hollow-bowl  construction. 

Modern  Separators. — Since  the  year  when  the  Danish  Weston 
and  the  De  Laval  machines  were  invented,  many  different 
types  of  separators  with  different  contrivances  within  the  bowl 
have  been  put  upon  the  market.  Baron  Bechtelsheim,  of 
Munich,  is  given  the  credit  of  having  discovered  that  certain 
contrivances  on  the  inside  of  the  machine  increase  the  efficiency 
and  capacity  for  skimming.  This  discovery  was  made,  accord- 
ing to  J.  H.  Monrad,1  in  1890.  This  invention  was  bought  by 
the  De  Laval  Company. 

The  principal  part  of  practically  all  the  separators  is  a  bowl 
rotating  in  a  vertical  position,  with  or  without  contrivances 
inside  the  bowl.  Machines  having  a  bowl  rotating  in  a  horizontal 
position  are,  so  far  as  the  authors  know,  not  in  use  at  the  present 
time.  Such  a  machine  was  once  manufactured  at  Hamburg, 
Germany,  and  was  called  "  Peterson's  Centrifugal  Machine." 
Another  German  machine,  called  "  The  Page,"  was  also  manu- 
factured in  the  horizontal  bowl  style. 

From  the  above  it  will  be  noticed  that  four  separate  steps 
are  recognizable  in  the  evolution  and  improvement  of  separators: 

1.  Revolving  Bucket  Centrifuge; 

2.  Intermittent  Hollow  Bowl; 

3.  Continuous  Hollow  Bowl; 

4.  Continuous  Separator  with  contrivances  within  the  Bowl. 
The  science  and  practice  of  separation  of  milk  and  cream  have 

1  Dairy  Messenger,  Jan.,  1892,  p.  9. 


158 


SEPARATION  OF   CREAM 


seemingly  reached  a  high  state  of  efficiency.  It  seems  almost 
improbable,  considering  the  many  new  improved  separators  on 
the  market,  that  any  other  great  improvement  could  be  made 
which  would  add  a  separate  stage  to  the  improvement  of  our  best 
centrifugal  milk  separators  of  to-day. 

Classification  of  Separators. — Owing  to  the  many  different 

standard  types  of  separators 
now  on  the  market,  it  is  im- 
possible to  describe  each  one 
in  detail.  For  this  reason  the 
classification  appearing  below 
has  been  made.  There  are 
undoubtedly  many ,  other 
types,  especially  in  foreign 
countries,  with  which  the 
writers  are  not  familiar,  and 
which  are  not  mentioned 
here.  The  following  classi- 
fication will,  in  some  meas- 
ure, illustrate  the  different 
makes  of  separators  on  the 
market  to-day : 

Many  of  these  separators 
which  cause  the  milk  to  pass 
up  and  down  in  vertical  sheets  have  the  bowl  contrivances  corru- 
gated and  perforated  with  holes  so  that  the  skim-milk  and  cream 
also  assume  a  partly  horizontal  direction. 

Process  of  Separation. — From  the  illustrations,  the  structure 
of  the  more  common  types  of  separator  bowls  is  readily  under- 
stood. The  whole  milk  may  be  made  to  enter  at  the  bottom  or 
top  of  the  bowl  when  revolving.  In  the  Sharpies,  it  enters  at  the 
bottom,  the  more  common  way  is  to  have  it  enter  at  the  top. 
As  the  milk  enters  the  bowl  and  is  exposed  to  the  centrifugal  force, 
it  immediately  begins  to  separate  into  three  distinct  layers.  The 
centrifugal  force  acting  in  a  horizontal  direction  forces  the 
heaviest  portions  of  the  milk  and  the  precipitated  albuminoids, 
ash,  filth,  and  a  multitude  of  germs  over  next  to  the  wall  of  the 


Fig.  47. — The  Simplex  separator. 


CENTRIFUGAL  CREAMING 


159 


Separators 


'  Hollow  bowl.  . .    < 

De  Laval  (old  style). 

Sharpies. 

Omega 

r  Cause  milk  to 

Empire. 

pass  in  thin 

Davis. 

Farm  sep- 

sheets verti- 

United States. 

arators. 

cally  in  bowl 

National. 
,  Reid. 

Contrivances 

Dairy  Queen. 

in  bowl. 

De  Laval. 

Cause  milk  to 

Peerless. 

separate  into 

Swea. 

almost  hori-  - 

Westphalia 

zontal     thin 

(Cleveland) 

sheets. 

Iowa. 
Internat.  Cream 

Harvester. 

'  Improved  Danish  Weston  (Reid.) 

Hollow  bowl 

Sharpies  (old  style). 
1  De  Laval  (old  style). 

Creamery 

Cause  milk  to 

United  States. 

power 

pass  in  thin 

Simplex. 

separa- 
tors. 

sheets  verti- 

Sharpies     (new 

cally  in  bowl. 

style). 

Contrivances  in  ■ 

bowl. 

Cause  milk  to 

separate  in  al- 

De Laval. 

most  horizon- 

Springer. 

tal  sheets. 

separator  bowl,  and  into  a  solid  and  more  or  less  gelatinous  layer, 
which  is  known  as  the  "  separator  slime."  In  very  impure  milk 
this  substance  is  so  plentiful  that  it  is  likely  to  clog  the  separator 
in  a  very  short  time,  and  before  much  separation  is  accomplished 
it  is  necessary  to  clean  out  the  bowl.  The  second  layer  is  the 
skim-milk,  while  the  cream,  being  the  lightest,  is  forced  to  the 
center  of  the  bowl  and  forms  the  third  portion  mentioned.  There 
is  no  distinct  line  of  demarcation  between  the  layers  of  skim-milk 
and  cream.  They  overlap  each  other  and  form  a  sort  of  zone, 
rather  than  a  sharp  separation.  The  richest  cream  is  nearest  the 
center  of  the  bowl,  and  gets  thinner  toward  the  outer  portion  of 
the  bowl;   consequently,  by  turning  the  outlet  for  the  cream,  or 


160 


SEPARATION  OF  CREAM 


cream  screw,  nearer  the  center  of  the  bowl,  the  cream  is  increased 

in  richness.  Turning  it  away 
from  the  center  causes  the  cream 
to  be  thinner.  The  skim-milk 
that  is  forced  clear  to  the  cir- 
cumference of  the  bowl  contains 
the  least  fat,  and  consequently 
the  skim-milk  is  always  first 
removed  from  this  portion  of 
the  bowl.  Usually  the  skim- 
milk  outlet  is  brought  in  towards 
the  center  of  the  bowl  at  one  end 
through  tubes  extending  from 
the  circumference  of  the  bowl. 
If  this  were  not  done,  some  diffi 
culty  would  be  involved  in  arranging  a  receiving-pan  for  the  dis- 
charged skim-milk.  If  the  skim-milk  were  discharged  near  the 
circumference  of  the  bowl,  it  would  come  out  with  a  heavy  force. 


Fig.  48. — The  Reid  separator. 


Fig.  49. — Showing  "  butter  extractor  " 
attached  to  De  Laval  separator.  The 
butter  extractor  is  not  known  to  be 
in  use  now . 


Fig.    50. — Showing    cross-section    of 
De  Laval  separator  bowl. 


CONDITIONS    AFFECTING   EFFICIENCY    OF    SEPARATORS     161 

Also,  if  the  outlet  for  the  skim-milk  were  near  the  circumference 
of  the  bowl  a  great  deal  more  power  would  be  required  to  run 
the  machine.  As  the  skim-milk  passes  through  the  tubes 
towards  the  center  it  gives  up  its  force.  The  nearer  the  skim- 
milk  outlet  can  be  brought  to  the  center  of  the  bowl,  the  more 
easily  will  the  machine  run. 

The  size  of  the  skim-milk  outlet  is  usually  such  that  it  bears  a 
certain  relation  to  the  size  of  inlet,  size  of  bowl,  and  speed  of  the 
machine.  Most  skim-milk  outlets  are  made  so  as  to  discharge 
from  .4  to  about  .9  or  a  little  more,  of  the  whole  milk  that  enters 
the  bowl.  The  remainder  is  the  cream,  which  is  forced  to  the 
center  of  the  bowl  and  discharged  through  the  cream  outlet. 

CONDITIONS  AFFECTING  EFFICIENCY  OF  SEPARATORS 

i.  Manner  of  Heating  Milk. — Owing  to  the  fact  that  fat- 
globules  rapidly  change  their  shape  and  properties  when  exposed 
to  heat  and  excessive  agitation,  it  is  essential  that  care 
should  be  taken  in  heating  milk  previous  to  skimming.  When 
fat-globules  are  heated  they  become  more  liquid,  and  if  stirred 
very  much  the  clusters  of  fat-globules  break  up  more  rapidly. 
The  individual  globules,  if  stirred  violently,  will  break  or  sub- 
divide into  several  small  ones.  The  higher  the  temperature 
of  the  milk,  the  more  fluid  it  becomes,  and  the  easier  the  separa- 
tion. If  milk  is  stirred  violently,  the  individual  fat-globules 
break  up  into  smaller  ones,  which  are  separated  from  milk  with 
difficulty .  The  table1  on  p.  162  illustrates  what  effect  the  dif- 
ferent degrees  of  agitation  of  milk  have  upon  the  efficiency  of 
separation. 

In  the  experiments  the  diameter  of  the  agitator  in  the  pas- 
teurizer was  14  inches.  The  speed  at  the  periphery,  at  250 
revolutions  per  minute,  was  15  feet  per  second. 

It  will  be  seen  from  the  table  (p.  162)  that  the  higher  the  speed 
of  the  agitator,  the  greater  the  difficulty  in  getting  a  complete 
separation.  Besides  the  speed  of  the  agitator  in  the  heating 
apparatus,  undoubtedly  the  shape  of  the  pasteurizer  is  a  factor 

1  Hoard's  Dairyman,  Fort  Atkinson,  Wis. 


162 


SEPARATION  OF  CREAM 


Milk  heated  in  vat,  not  pumped 

Milk  heated  in  pasteurizer,  200  rev.  of  agitator  per  min.  . 
Milk  heated  in  pasteurizer,  250  rev.  of  agitator  per  min .  . 
Milk  heated  in  pasteurizer,  300  rev.  of  agitator  per  min.  . 
Milk  heated  in  pasteurizer,  350  rev.  of  agitator  per  min .  . 
Milk  heated  in  pasteurizer,  400  rev.  of  agitator  per  min .  . 
Milk  heated  in  pasteurizer,  500  rev.  of  agitator  per  min .  . 

Milk  pumped  by  the  turbine  pump  at  1220  F 

Milk  pumped  by  the  turbine  pump  at    640  F .  .  . 

Milk  pumped  with  the  pump,  effective  at  1220 

Milk  pumped  with  the  pump,  effective  at    640 


Av.  Fat 

No  of 

Per  Cent 

Experi- 

in Skim- 

ments 

milk 

10 

.117 

8 

•115 

3 

.118 

8 

•134 

2 

•143 

7 

.198 

4 

.225 

3 

.129 

3 

.119 

3 

.117 

3 

.115 

in  determining  the  efficiency  of  the  subsequent  separation.  For 
instance,  the  milk  in  most  horizontal  pasteurizers  is,  even  at  low 
speed,  exposed  to  considerable  agitation. 

If  the  milk  is  suddenly  heated  from  a  low  temperature  to 
about  8o°  or  900  F.  and  then  skimmed,  the  heating  does  not 
facilitate  the  skimming  process  very  much.  It  is  essential  that 
the  milk  be  exposed  to  this  temperature  for  a  considerable  time. 
The  fat-globules  do  not  warm  as  rapidly  as  the  milk  serum.  This 
diminishes  the  difference  between  the  specific  gravity  of  the  two 
substances,  consequently  completeness  of  separation  becomes 
more  difficult.  If  milk  is  heated  to  a  high  temperature,  say,  for 
instance,  1700  F.,  the  separation  will  be  sufficiently  complete 
without  exposing  the  milk  for  any  length  of  time  to  that  temper- 
ature. 

Machines  are  now  made,  and  are  on  the  market,  which  will 
bring  the  milk  into  such  a  condition  that  the  fat-globules  cannot 
be  separated  from  it.  The  process  is  called  "  homogenization." 
It  consists  of  bringing  the  milk  under  certain  pressure,  and  then 
forcing  it  out  through  a  special  valve.  This  relief,  through  this 
special  valve,  breaks  up  the  existing  fat-globules  into  very 
minute  ones,  which  cannot  be  separated  from  the  milk  by 
gravity  mehtods,  and  which  it  is  impossible  to  separate  com- 
pletely  by   centrifugal  methods.      Homogenization  of  milk  is 


CONDITIONS  AFFECTING  EFFICIENCY  OF  SEPARATORS     163 

carried  on  to  some  extent  in  Europe.  The  process  practically 
insures  uniform  quality  to  the  milk  patrons  in  the  distribution 
of  milk  in  cities,  and  secures  a  more  uniform  consistency  of  the 
product. 

2.  Condition  of  the  Milk. — In  order  to  get  complete  separa- 
tion, and  keep  the  separator  in  good  running  order,  it  is  essential 
that  the  milk  should  be  in  as  good  physical  condition  as  possible. 
Coagulated,  slimy,  or  otherwise  viscous  milk  separates  with 
difficulty.  When  such  milk  is  on  hand  it  should  not  be  mixed 
with  the  milk  that  is  in  good  condition,  as  it  might  tend  to  coag- 
ulate more  of  the  good  milk,  and  the  coagulated  or  slimy  lumps 
are  likely  to  clog  the  separator.  Such  milk  should  be  left  until 
all  the  good  milk  has  been  separated.  Then,  if  the  coagulated 
or  slimy  milk  is  thoroughly  stirred  so  as  to  reduce  its  lumpiness, 
it  may  be  run  through  the  separator  successfully.  It  is  a  good 
plan  not  to  feed  the  separator  quite  so  heavily  when  this  quality 
of  milk  is  being  run  through.  If  the  inlet  is  partly  shut  off,  it  will 
usually  run  through  without  clogging.  Milk  containing  impuri- 
ties in  suspension  should  be  thoroughly  strained  previous  to 
separation. 

Overfeeding  the  Separator. — When  a  separator  is  being  over- 
fed with  milk  there  is  a  tendency  for  the  machine  to  do  less  com- 
plete work.  This  is  due  to  the  fact  that  the  more  milk  is  being 
fed  into  the  separator  the  less  time  it  will  be  subjected  to  the 
centrifugal  force.  It  is  possible  to  underfeed  the  separator  as 
well.  As  has  been  mentioned  before,  the  inlet  can  be  closed  to 
such  an  extent  as  to  cause  nearly  all  the  discharge  to  take  place 
through  the  skim-milk  tube. 

As  a  rule  when  the  machine  has  been  set  so  as  to  allow  the 
milk  to  flow  in  at  a  certain  rate,  it  will  continue  to  admit  prac- 
tically the  same  amount  of  milk  all  through  the  skimming  period. 
Among  the  conditions  which  may  alter  the  rate  of  inflow  to  some 
extent,  are  the  amount  of  heat  and  the  change  of  pressure,  due  to 
different  amounts  of  milk  in  the  receiving-vat.  Temperature 
will  slightly  affect  the  rate  of  inflow.  The  higher  the  tempera- 
ture, all  other  conditions  being  the  same,  the  more  milk  will  pass 
through  the  inlet. 


164  SEPARATION  OF  CREAM 

3.  Speed. — All  modern  machines  have  a  device  by  which  their 
speed  can  be  determined.  Most  speed  indicators  consist  of  a 
little  wheel,  which,  when  pushed  up  against  the  spindle  of  the 
separator  while  running,  turns  around  and  permits  the  calcu- 
lation of  the  speed  of  the  separator.  If  the  wheel  on  the  speed- 
indicator  makes  10  revolutions  during  ten  seconds,  the  machine 
turns  1000  times  during  the  same  time.  During  one  minute  the 
separator  will  run  six  times  as  many  revolutions,  or  6000,  as  ten 
seconds  is  one-sixth  of  a  minute.  Most  speed-indicators  are  so 
adjusted  as  to  turn  one  revolution  for  every  100  revolutions  of  the 
machine.  The  higher  the  speed,  the  more  thorough  is  the  sepa- 
ration. Nearly  all  machines  are  balanced  to  do  the  best  work  at  a 
certain  definite  speed,  varying  with  different  machines,  and 
indicated  in  the  directions  for  operating.  It  is  essential  that  the 
machine  should  be  brought  up  to  speed  gradually,  and  no  milk  be 
allowed  to  flow  through  it  until  after  it  has  acquired  its  full  speed. 

During  the  run,  all  machines  are  likely  to  vary  more  or  less 
in  speed,  owing  to  different  causes.  Pulleys  are  likely  to  slip 
on  the  shaft,  and  belts  are  likely  to  become  loose,  and  thus 
cause  variations  in  the  speed.  The  steam  pressure  may  get  low, 
and  cause  all  of  the  machinery  in  the  creamery  to  run  more 
slowly.  This  cause,  however,  is  not  a  very  common  one  where 
belt  separators  are  used.  If  the  engine  has  an  automatic  gov- 
ernor on  it,  the  speed  is  usually  quite  uniform.  Where  steam- 
turbine  machines  are  used,  the  speed  of  the  machine  is  more  likely 
to  vary  with  the  different  amounts  of  steam  pressure  on  the 
boiler.  With  turbine  separators  it  is  very  essential  to  keep  an 
even  steam  pressure.  Some  turbine  separators  have  a  safety- 
valve  attached  to  prevent  too  high  speed. 

The  reason  why  the  prevention  of  a  variation  in  speed  is  so 
essential  is  that  a  slight  variation  in  the  speed  has  a  compara- 
tively large  effect  upon  reducing  or  increasing  the  centrifugal 
force.  The  centrifugal  force  generated  in  a  machine  varies 
according  to  the  diameter  of  the  bowl,  and  according  to  the 
speed  of  the  machine.  The  greater  the  diameter  of  the  bowl, 
the  less  speed  or  velocity  is  required  in  order  to  get  a  certain 
force.     The  centrifugal  force  varies  in  direct  proportion  to  the 


CONDITIONS  AFFECTING  EFFICIENCY  OF  SEPARATORS      165 

diameter  of  the  bowl;  that  is,  if  the  diameter  of  the  bowl  be 
doubled,  then  at  the  same  speed,  the  centrifugal  force  has  been 
doubled.  The  centrifugal  force  varies  in  quadratic  proportion 
to  the  speed  of  the  machine;  that  is,  if  the  speed  of  the  separator 
is  doubled,  the  centrifugal  force  is  increased  four  times.  From 
this  it  will  be  seen  that  speed  is  a  great  factor  in  determining  the 
centrifugal  force  generated.  It  is  not  a  good  plan  to  have  the 
diameter  of  the  bowl  too  large,  for  the  following  reasons:  A  large 
bowl  is  more  likely  to  be  thrown  out  of  balance;  it  is  harder  to 
keep  on  the  bearings;  and  it  is  heavier  and  more  unhandy  to 
handle.  For  these  reasons  it  is  better  to  lessen  the  diameter  of 
the  bowl  and  increase  the  speed.  This,  of  course,  is  true  only  to  a 
certain  limit. 

Steadiness  in  Running. — Smooth  running  of  a  separator  is 
one  of  the  first  essentials.  If  a  machine  runs  roughly,  there  will 
not  be  good  separation,  and  it  is  dangerous  to  run  it.  The 
bowl  itself  is  likely  to  jump  out,  or  burst.  The  causes  for 
unsteadiness  in  running  are  many.  It  may  be  due  to  a  bent  or 
sprung  spindle ;  the  machine  not  standing  level ;  changing  covers 
to  bowls;  using  clamps  which  do  not  fit  the  bowl  cover ;  unclean, 
worn-out  bearings;  condition  of  the  bowl,  and  contrivances 
inside  the  bowl;  and  dented  and  rusty  bowls.  Occasionally  it 
happens  that  a  machine  is  run  backwards.  This  is  likely  to 
cause  the  cover  of  the  bowl  to  run  off. 

Thickness  of  Cream. — The  efficiency  of  skimming  depends 
to  some  extent  upon  the  thickness  of  the  cream  skimmed.  Most 
separators,  however,  will  skim  within  quite  a  wide  range  as  to 
thickness.  The  richness  of  cream  usually  skimmed  by  separators 
ranges  from  25  per  cent  to  50  per  cent.  Most  separators,  how- 
ever, will  do  good  skimming  even  if  the  cream  contains  as  high 
as  60  per  cent  fat.  This,  however,  should  be  considered  to  be 
about  the  maximum,  in  order  to  get  the  best  results  from  a  sep- 
arator. 

Slush  in  Bowl. — As  has  been  mentioned  before,  there  is 
always  a  thick,  slimy  substance  which  adheres  to  the  bowl-wall. 
The  composition  of  separator-slime  is,  according  to  Fleischmann, 
as  follows: 


166  SEPARATION  OF  CREAM 

Water 67.3 

Fat 1.1 

Caseous  matter 25.9 

Other  organic  substances 2.1 

Ash 3.6 


100.  o 


At  the  center  of  the  bowl,  or  along  the  perpendicular  axis, 
there  is  always  considerable  cream.  It  is  practically  impossible 
to  get  all  the  cream  out  of  the  bowl,  even  if  it  is  flushed  with 
much  water.  The  amount  of  slush  varies  somewhat  with  the 
different  kinds  of  separators,  and  it  is  essential  that  this  amount 
should  be  taken  into  consideration  when  the  comparative 
skimming  efficiency  of  different  separators  is  considered.  When 
the  test  extends  over  a  comparatively  long  period,  and  the  milk 
skimmed  amounts  to  several  thousand  pounds,  the  bowl  slush 
does  not  greatly  affect  the  conditions  for  comparative  results; 
but  when  the  test  is  short,  and  only  a  hundred  pounds  of  milk,  or 
thereabout,  is  skimmed,  the  amount  of  fat  left  in  the  bowl-slush 
will  have  considerable  influence  upon  the  choice  of  a  machine. 

General  Remarks. — In  order  to  keep  the  separator  in  good 
running  order,  it  must  receive  care.  The  belt  should  neither  be 
too  tight,  nor  too  loose.  If  too  tight  it  is  likely  to  bind,  heat, 
and  set  the  bearings  of  the  separator.  If  too  loose  it  is  likely 
to  slip,  and  to  wear  out  more  quickly.  The  machine  should  be 
well  oiled.  It  is  better  to  use  a  trifle  too  much  oil  than  not 
enough.  If  a  bearing  is  once  heated,  the  machine  will  never 
run  as  well  again. 

The  bowl  should  be  handled  with  great  care.  Bowls,  or 
parts  belonging  to  the  bowl,  can  be  kept  from  rusting  by  boiling 
them  in  water,  or  by  steaming  them  thoroughly  after  they 
have  been  cleaned.  If  scalding-hot  water  is  used  before  the  milky 
portion  has  been  washed  off,  the  albuminoids  will  be  scalded  on 
to  such  a  degree  that  it  will  be  difficult  to  get  them  off.  This 
applies  to  all  dairy  and  creamery  utensils.  It  is  said  that  tin 
or  ironware  may  be  prevented  from  rusting  by  being  dipped  into 


CONDITIONS  AFFECTING  EFFICIENCY  OF  SEPARATORS      167 

hot  water  after  washing.  If  the  bowl,  pail,  or  whatever  utensil 
it  may  be,  is  turned  over  to  drain  after  being  dipped  in  hot  water, 
the  heat  taken  up  by  the  utensil  will  in  a  short  time  perfectly 
dry  the  apparatus.  If  the  bowl  is  steamed,  it  should  be  heated 
thoroughly  to  make  it  dry  quickly. 

If  the  milk  supply  gets  short  during  the  run,  and  it  is  necessary 
to  run  the  machine  without  feeding  milk,  the  machine  should 
always  be  flushed  with  lukewarm  water.  This  will,  in  a  measure, 
prevent  clogging.  Scalding-hot  water  should  never  be  used  for 
flushing  the  separator.  The  cream  and  skim-milk  tubes  should 
be  carefully  cleaned,  with  the  special  wire  provided  for  that  pur- 
pose, each  time  the  machine  is  washed.  The  contrivances  on  the 
inside  of  the  bowl  should  also  be  handled  with  care  so  as  not  to 
injure  them  in  any  way.  They  should  be  treated  with  hot  water, 
as  mentioned  above,  in  order  to  keep  them  from  rusting. 

When  the  bowl  is  not  to  be  used  for  some  time,  it  should  be 
oiled  well  to  prevent  it  from  rusting.  It  is  easier  to  oil  a  sepa- 
rator bowl  than  it  is  to  scour  the  rust  off  later  on. 


CHAPTER  XIII 
FARM  SEPARATORS 

The  factors  which  influence  the  richness  of  cream  are  dealt 
with  in  Part  II  of  the  chapter  on  "  Variation  of  Fat  in  Milk  and 
Cream,"  while  those  affecting  the  efficiency  of  skimming  are 
dealt  with  in  the  chapter  on  "  Separation  of  Cream."  These 
factors  apply  equally  to  power  and  farm  separators.  The  con- 
ditions under  which  farm  separators  are  operated  warrant  this 
separate  chapter  upon  this  subject. 

Introduction  of  Farm  Separators. — Small,  or  hand,  separators 
have  been  manufactured  for  a  great  many  years,  but  their 
general  adoption  is  of  comparatively  recent  date.  For  instance, 
it  was  in  1894 — not  so  very  long  ago — that  hand  separators 
were  introduced  into  the  large  dairy  state  of  Iowa.  Thirty  years 
ago  practically  all  of  our  creameries  were  milk-receiving  cream- 
eries, while  to-day  the  great  bulk  of  our  creamery  butter  is  made 
from  cream  separated  on  the  farm  by  means  of  hand  or  farm 
separators.  Naturally  the  people  of  the  Central  West  (Iowa, 
Kansas,  Nebraska,  Missouri,  Minnesota,  Illinois  and  Indiana) 
have  been  foremost  in  the  development  of  this  system,  as  it  is 
best  suited  to  their  conditions.  It  permits  many  of  the  farmers 
who  engage  in  dairying  in  a  comparatively  small  way  to  become 
patrons  of  creameries  located  at  considerable  distances  from 
them. 

Reasons  for  Introducing  Farm  Separators. — It  requires  an 
investment  of  about  $100  to  purchase  a  hand  separator;  it  may 
therefore  be  concluded  that  some  good  reasons  lead  farmers  to 
make  such  an  investment.  The  chief  of  these  may  be  briefly 
stated  as  follows : 

(1)  The  farmer  is  able  to  skim  the  milk  immediately  after  it 
has  been  drawn,  thereby  enabling  him  to  feed  the  milk  while 

168 


REASONS  FOR  INTRODUCING  FARM  SEPARATORS 


169 


it  is  in  a  warm,  sweet,  unadulterated  condition.     If  he  hauled 
the  milk  to  the  creamery,  the  skim-milk  would  be  likely  to  come 
back  in  a  sour  and  curdled  condition,  and  at  times  watery.     (In  a 
well-conducted  creamery  these  latter  conditions  do  not  existT) 
(2)  The  high  cost  of  hauling  in  many  instances  makes  it 


Fig.  51. — The  Omega  hand  separator. 

almost  impossible  to  get  the  milk  to  the  creamery.  Even  if 
the  roads  are  good,  the  distance  to  the  creamery  is  frequently 
so  great  that  it  is  impossible  to  get  haulers,  nor  is  it  practicable 
for  every  farmer  to  haul  his  own  milk  every  day.  Especially 
is  this  so  during  the  busy  season  of  the  year.     In  the  fall,  when 


170 


FARM   SEPARATORS 


milk  is  scarce,  it  is  almost  impossible  for  the  hauler  to  get  enough 
milk  to  make  it  profitable.  In  many  cases  it  is  necessary  to  p^y 
an  excessive  price  for  hauling  milk. 

When  cream  routes  are  established  instead  of  milk  routes, 
one  hauler  can  usually  cover  as  much  territory  as  three  could 
under  the  milk  system.  Two  thousand  pounds  of  milk,  testing 
4  per  cent  and  containing  80  pounds  of  fat,  would  represent 

approximately  a  load  of  milk.  At  25 
cents  per  100  pounds,  this  would  mean 
a  cost  of  $5.00  for  getting  that  much 
milk  hauled.  If  the  same  amount  of 
butter-fat  were  hauled  in  the  form  of 
cream,  it  could  be  gathered  for  about 
3  cents  per  pound  of  fat,  or  the  cost 
of  hauling  in  this  particular  case  would 
be  $2.40.  Under  the  milk  system  it 
would  be  necessary  to  haul  the  n  ilk 
to  the  creamery  every  day,  while  under 
the  cream  system  it  is  usually  gathered 
every  other  day  in  the  summer,  and 
every  three  days  in  the  winter.  It  is 
usually  considered  that  there  is  a  saving 
of  about  2  to  3  cents  per  pound  of 
butter-fat  in  hauling,  by  making  use 
Fig.  52.— The  De  Laval  hand  0f  the  cream  system  instead  of  the 
separator  (Baby  No.x).         ^   ^^      ^    rf   ^^   would 

vary  according  to  local  conditions. 

3.  The  use  of  hand-separators  makes  farmers  more  inde- 
pendent than  they  are  under  the  whole-milk  system.  They 
are  not  compelled  to  support  their  local  creamery  unless  they 
deem  it  advisable.  They  can  ship  their  cream  to  any  place  that 
they  may  choose.  If  the  butter  from  the  hand-separator  cream 
is  to  be  of  as  good  quality  as  that  made  by  the  whole-milk  system, 
the  cream  should  be  delivered  as  often  as  possible.  Every  day  is 
preferable  to  every  other  day.  In  case  frequent  delivery  is  made, 
it  becomes  quite  essential  for  the  farmer  to  patronize  the  local 
creamery,  as  very  few  farmers  keep  sufficient  cows  to  get  enough 


OBJECTIONS  TO  FARM  SEPARATORS 


171 


cream  to  pay  them  to  ship  by  rail  every  day.     Usually  it  does 
not  cost  much  more  to  ship  a  can  full  of  cream  than  it  does  to 

ship  it  half  or  three-quarters  full. 

Objections  to  Farm  Separators. — Under  the  present  system 


■P1 


Fig.  53. — Simplex  hand  separator  and  the  different  parts  of  bowl. 


of  shipping  cream  long  distances  the  quality  of  the  butter  made 
from  it  is  often  of  a  lower  grade  than  that  made  from  good  whole 
milk.  This  is  not  due  to  any  fault  of  the  system,  but  to  the  poor 
care  which  the  separator  and  cream  may  receive.  The  separator 
on  the  farm  is  sometimes  kept  in  an  unsuitable  place,  often  in  the 


172 


FARM  SEPARATORS 


barn.  If  the  milk  is  separated  in  such  a  place  it  will  absorb  odors 
and  undesirable  taints.  The  cream  is  not  always  taken  care  of 
properly  after  it  is  separated.  The  separators  may  not  be 
cleaned  well.  A  separator  cannot  be  kept  in  good  condition  by 
simply  flushing  out  the  bowl  with  cold  water  at  the  end  of  each 
separation.  It  must  be  taken  apart  at  the  close  of  each  skimming, 
and  all  the  parts  must  be  washed  thoroughly  in  lukewarm  water, 
and  then  scalded.     The  time  and  power  required  to  skim  the 


Fig.  54. — Sharpies  separator  and  parts  of  bowl. 


milk  and  to  care  for  the  cream  are  in  many  instances  regarded  as 
objections  to  the  system. 

Thickness  of  Cream. — Most  butter-makers  at  central  plants 
prefer  cream  containing  about  30  to  40  per  cent  of  fat.  Such 
cream  is  not  thick  enough  to  cause  any  inconvenience  in  sampling 
and  weighing.  It  can  be  diluted  with  a  good  starter  and  ripened 
without  becoming  so  thin  as  to  produce  unfavorable  conditions 
for  churning.  By  some  it  is  deemed  advisable  to  skim  even 
thicker  than  this,  up  to  50  per  cent.  Cream  containing  this  much 
fat,  however,  is  difficult  to  handle,  especially  during  cold  weather. 
It  becomes  so  stiff  that  it  is  difficult  to  pour,  and  there  is  also 


THICKNESS  OF  CREAM 


173 


danger  of  losing  more  or  less  cream  through  its  adhering  to  the 
sides  of  the  cans. 

A  thick  cream  is  advisable  from  the  farmer's  standpoint. 


Fig.  55. — Peerless  hand  separator  and  cross-section  of  bowl. 


Fig.  56.— Agos  hand  tester. 

The  thicker  the  cream  is,  the  more  skim-milk  he  will  retain  on 
the  farm  for  feeding  purposes.  It  can  also  readily  be  seen 
that  if  thin  cream  is  skimmed  greater  can  capacity  is  necessary, 


174 


FARM   SEPARATORS 


and  the  express  charges  will  be  heavier  than  if  the  thicker  cream 
were  skimmed.  Rich  cream  does  not  sour  so  rapidly  as  does  thin 
cream. 

The  richness  of  cream  can  be  readily  ascertained  by  the  use  of 
a  Babcock  test,  which  every  farmer  should  have  in  his  possession. 
A  whole  outfit  for  testing  fat  in  cream  or  milk  can  be  had  for 
about  $10.00  from  any  creamery  supply-house.  By  the  use  of 
such  a  test,  the  farmer  can  test  his  cream  and  skim-milk.  He 
can  also  test  the  milk  of  each  individual  cow  in  the  herd,  thereby 
ascertaining  which  ones  are  profitable.  By  the  use  of  such  a  test 
on  the  farm,  the  farmer  can  test  his  cream  daily,  and  compare 


Fig.  57. — Tread-power  attached  to  United  States  hand  separator. 


results  with  those  from  the  creamery,  thereby  enabling  him  to 
detect  any  mistake  which  may  happen  at  the  creamery. 

Power  for  Farm  Separators. — Hand-power  is  often  men- 
tioned as  an  objection  to  farm  separators.  When  a  considerable 
quantity  of  milk  is  to  be  skimmed,  it  is  certainly  hard  work  to 
skim  with  hand-power.  Windmills  could  not  well  be  used  as 
they  do  not  give  uniform  speed.  Tread-power  is  often  used  to 
run  farm  separators  and  is  very  well  adapted  to  this  purpose,  as  it 
is  steady  and  uniform,  and  does  not  cost  anything  after  the 
apparatus  has  once  been  purchased.  The  power  can  be  supplied 
by  using  different  kinds  of  animals.     Sheep,  goats,  dogs,  and 


POWER  FOR  FARM   SEPARATORS 


175 


Fig.  5 8. —Showing  the  height  to  which  cream  free  from  air  bubbles  must  be  raised 
in  a  pipette  to  get  18  grams  of  cream.  It  shows  that  to  measure  cream  in  a 
pipette  is  inaccurate  in  cream  testing.     (Iowa  State  Dairy  Com.  Report,  1903.) 


176  FARM   SEPARATORS 

bulls  are  used  for  this  purpose.  The  process  does  not  usually 
last  very  long,  and  the  work  is  not  considered  heavy.  Steam  is 
good  power,  but  it  is  hardly  ever  obtainable  on  the  farm. 
Small  gasoline-engines  are  also  used  very  successfully. 

The  machine  should  always  run  smoothly  in  order  to  get 
efficient  skimming.  It  should  never  be  stopped  and  started  with 
a  jerk.  If  it  is  started  slowly  there  will  be  less  danger  of  breaking 
any  o*  the  gearing  parts.  The  bowl  and  inside  parts  should  be 
kept  from  rusting  as  described  previously  on  page  167.  The 
bearings  should  be  well  oiled.  It  is  a  good  plan  to  have  an  extra 
bearing  or  two  on  hand,  so  that  if  one  happens  to  wear  out 
another  one  can  be  put  in.     The  bearings  should  be  cleaned  at 


Progeny  of  a 
single  germ  in    0 
twelve  hours 


Fig.  59. — Showing  the  effect  of  cooling  milk  on  the  growth  of  bacteria.     The  bene- 
ficial results  of  early  chilling  are  readily  apparent.     (From  Bui.  62,  Wis.) 

intervals.  When  kerosene  is  occasionally  used  on  the  bearings 
they  do  not  need  to  be  cleaned  so  often,  because  it  keeps  them 
from  gumming.  The  machine  should  be  turned  at  the  proper 
speed,  as  indicated  in  the  directions.  A  thicker  cream  will 
result  from  rapid  turning;  consequently  more  skim-milk  will  be 
obtained.  Slow  turning  causes  inefficient  skimming  and  thinner 
cream. 

Care  of  Cream  on  the  Farm. — The  first  step  in  the  production 
of  good  cream  is  clean  milking.  This  can  be  accomplished  only 
when  barn,  cows,  and  utensils  are  clean.  It  is  a  good  plan  to 
dampen  a  cloth,  and  wipe  off  the  cow's  udder  and  sides  previous 
to  each  milking.     The  milker  should  never  wet  his  hands  while 


CARE  OF  CREAM  ON  THE  FARM 


177 


milking.     Dust  should  not  be  stirred  up   in   the  barn  during 
milking,  as  the  dust  particles  carry  with  them  a  large  number  of 


Fig.  60. — The  condition  of  the  cow  shown  in  this  cut  is  favorable  for  the  accumu- 
lation of  loose  dirt.     (Bui.  84,  111.) 


undesirable  germs,  and  when  these  settle  in  milk  they  are  likely 
to  produce  taints.     If  cloth  strainers  are  used  they  should  be  kept 


178 


FARM   SEPARATORS 


scrupulously  clean.     It  is  advisable  not  to  use  them  at  all,  as 
good  sanitary  wire-gauze  strainers  are  inexpensive. 


Fig.  6i. — A  clean  cow.     The  dirt  cannot  adhere  to  this  cow  to  so  great  an  extent 
as  to  the  one  shown  in  Fig.  60.     (Bui.  84,  111.) 

If  these  conditions  are   complied  with,   and   the  separator 
is  kept  in  a  good  clean  condition,  the  milk  will  have  compara- 


DISPOSITION  OF  THE  CREAM  179 

tively  few  germs  in  it.  Some  germs,  however,  will  enter  the 
milk,  and  in  order  to  keep  them  from  developing,  it  is  essential 
to  cool  the  cream  or  milk  immediately.  Low  temperature 
retards  and  practically  prevents  the  development  of  germ  life. 
It  is  a  well-known  fact  that  when  milk  is  kept  cool,  it  will  remain 
sweet  much  longer  than  if  kept  at  a  high  temperature.  Two 
milkings  or  skimmings  should  never  be  mixed  unless  both  are  well 
cooled  first.  In  order  to  cool  cream  quickly,  it  should  be  stirred 
during  cooling.  The  ordinary  four-gallon  shot-gun  cans  are 
good  and  suitable  for  keeping  milk  and  cream.  They  have 
a  large  cooling  surface  in  proportion  to  their  cubical  content. 
The  milk  or  cream  should  be  cooled  as  low  as  the  water  will 
cool  it,  and  even  lower  than  this  if  ice  is  obtainable.  In  keeping 
milk,  the  temperature  should  never  go  above  6o°  F.  Cooling  to 
500  F.,  if  it  can  be  accomplished,  is  much  more  desirable  for 
keeping  milk  or  cream  in  good  condition. 

If  considerable  milk  is  handled,  it  is  well  to  provide  a  milk- 
house.  It  should  be  built  large  enough  to  contain  the  sepa- 
rator, water-tank,  and  other  utensils  necessary  for  home  butter- 
making,  such  as  a  churn  and  butter- worker.  There  should  be 
plenty  of  windows  on  all  sides  to  give  good  ventilation.  The 
water-tank  should  be  connected  directly  with  the  well,  so  that 
the  water  can  be  pumped  directly  to  the  tank  holding  the  milk 
and  cream.  From  this  place  the  water  can  be  run  out  into  the 
stock-tank.  This  arrangement  allows  the  milk  to  be  kept  at 
the  lowest  possible  temperature. 

It  is  just  as  essential  to  cool  the  milk  during  the  winter  as  it  is 
during  the  summer.  By  pumping  water  through  this  tank 
practically  all  the  time,  the  water  in  the  tank  will  be  kept  from 
freezing.  It  is  well  to  keep  the  surface  of  the  water  higher 
than  the  surface  of  the  milk  in  the  can.  This  will  prevent  the 
milk  from  freezing  so  easily.  If  the  cold  is  too  severe,  a  tank- 
heater  can  easily  be  secured  which  will  moderate  the  temperature 
a  trifle. 

Disposition  of  the  Cream. — There  are  two  ways  of  disposing 
of  cream  on  the  farm:  (1)  selling  it  to  creameries  or  other  parties, 
and  (2)  making  it  into  butter  on  the  farm.     The  former  method  is 


180 


FARM   SEPARATORS 


usually  the  most  advantageous.  Creameries,  as  a  rule,  are 
better  equipped  to  control  the  quality  of  butter.  The  price  per 
pound  of  butter-fat  is  usually  about  2  cents  below  "  New  York 
Extras."  A  few  of  the  best  creameries  are  able  to  pay  more 
than  that. 

Shipping  of  Cream. — If  cream  is  sent  or  shipped  to  cream- 
eries and  central  plants,  it  is  essential  that  it  be  delivered  as 
frequently  as  possible,  and  that  it  be  delivered  in  cans  which 
will  help  keep  it  in  good  condition.  If  cream  is  to  be  hauled 
any  great  distance  and  exposed  to  the  sun,  it  is  advisable  to  use 
special  jacketed  cans,  which  retard  the  transmission  of  heat. 
It  is  a  good  plan  to  cover  the  cans  with  a  wet  sack  or  cloth  during 
the  summer,  and  the  use  of  a  dry  sack  on  the  outside  in  th$  winter 
often  prevents  the  cream  from  freezing. 

Making  Butter  on  the  Farm. — If  cream  is  kept  in  good  condi- 
tion and  proper  skill  is  ap- 
plied, the  best  of  butter  can 
be  made  on  the  farm.  The- 
oretically, better  butter  can 
be  made  on  the  farm  than  at 
the  creamery,  because  all 
conditions  can  be  controlled 
better.  In  the  creameries 
one  can  of  bad  cream  mixed 
with  a  quantity  of  good  cream 
is  likely  to  contaminate  and 
injure  the  whole  lot.  The 
cream  which  is  to  be  made 
into  butter  on  the  farm  should 
not  be  over-ripened  before 
it  is  churned.  In  creameries, 
starters  are  used  to  set  up  a 
quick  and  desirable  fermentation  in  the  cream ;  conditions .  are 
usually  such  on  the  farm  that  it  is  not  convenient  and  practical 
to  use  a  starter.  It  is  very  essential  that  the  cream  be  cooled  to 
a  low  temperature  (500  F.)  and  left  at  this  temperature  for  at 
least  two  hours  before  it  is  churned ;  otherwise  the  butter  is  likely 


Fig.  62. — A  barrel  churn. 


MAKING  BUTTER  ON  THE  FARM 


181 


Fig.  63. — Skinner  butter- worker. 


to  be  greasy  and  salvy.     Butter  should  be  colored  and  salted 

to    suit    the    market    and 

season.     About  one-half  to 

one  ounce  of  salt  to  1  pound 

of    butter    usually    gives 

good  results. 

If  a  local  trade  can  be 

secured,  it  is  not  necessary 

to    pack   the    butter    into 

tubs.     In  this  case  it  may 

be   kept   in   earthen   jars. 

If   no   local    trade  can  be 

secured,  and  it  is  essential  to  ship  the  butter,  20-  or  30-pound 

tubs  should  be  used.  If  a 
good  quality  and  constant 
supply  of  butter  can  be 
secured  throughout  the 
whole  year,  it  is  an  easy 
matter  to  find  an  excellent 
market  at  hotels  or  good 
restaurants.  (For  a  more 
detailed  discussion  of  but- 
ter-making, see  Chaps. 
XVII  and  XVIII.)  Putting 
up    butter  in    prints    and 

wrapping  them  in  parchment  paper  which    bears  the  maker's 

name  usually  increases  its  selling  price. 


Fig.  64. — Wizard  butter  worker  (Creamery 
Package  Mfg.  Co.) 


182 


FARM   SEPARATORS 


CHAPTER  XIV 
NEUTRALIZATION 

The  "  Neutralization  "  of  Cream 

Neutralization. — The  principle  of  neutralization  is  not  a  new- 
one.  Its  application  in  the  laboratory  is  practically  as  old  as 
the  science  of  chemistry,  but  its  application  to  cream  is  compara- 
tively recent. 

The  principle  is  easily  explained  and  understood.  In  chem- 
istry there  are  two  large  classes  of  substances  which  are  opposite 
to  each  other  in  action  and  have  a  strong  affinity  for  each  other, 
namely,  bases  (which  include  alkalies)  and  acids.  A  base  and 
an  acid,  when  brought  together,  react  upon  each  other  to  form  a 
new  substance  which  is  neither  an  acid  nor  an  alkali,  and  is 
called  a  salt.  For  example,  when  hydrochloric  acid  and  caustic 
soda  react  upon  each  other  common  salt  and  water  are  formed, 
thus, 

HC1        +     NaOH     -*     NaCl      +     H20 

(Hydrochloric  Acid)        (Caustic  Soda)        (Common  salt)  (Water) 

Again,  when  either  quicklime  or  slaked  lime  (hydrate  of  lime) 
reacts  with  hydrochloric  acid  they  form  calcium  chloride,  which 
is  the  salt  commonly  used  for  making  the  brine  used  in  connec- 
tion with  refrigerator  systems,  as  it  can  be  reduced  to  a  very  low 
temperature  without  freezing. 

CaO     +     2HCI     =       CaCl2       +     H20 

(Quicklime)  (Calcium  chloride) 

or 

Ca(OH)2     +     2HCI     -     CaCb     +     2H20 

(Slaked  lime) 

183 


184  NEUTRALIZATION 

A  definite  quantity  of  a  given  alkali  will  always  neutralize  a 
definite  quantity  of  a  given  acid.  To  take  a  concrete  example: 
If  upon  trial  we  find  that  it  takes  8  c.c.  of  a  certain  alkali  solution 
to  neutralize  10  c.c.  of  a  given  acid  solution,  subsequent  trials 
will  show  that  they  always  combine  with  or  neutralize  each  other 
in  exactly  the  same  proportions.  In  a  test  of  this  kind  we  use 
an  "  indicator  "  to  tell  us  when  the  solution  tested  changes  from 
an  acid  to  an  alkali.  If  phenolphthalein  be  used  it  remains 
colorless  so  long  as  the  medium  is  acid,  but  as  soon  as  the  acid  is 
all  neutralized  and  the  liquid  becomes  alkaline  to  the  slightest 
degree,  this  indicator  turns  red.  Litmus  shows  blue  when  the 
medium  is  alkaline  and  red  when  it  is  acid. 

The  principle  of  neutralization  has  been  applied  in  dairy 
work  for  many  years,  in  the  form  of  the  different  alkali  tests  used 
in  cheese-  and  butter-making  to  determine  the  acidity  of  the  milk 
or  cream.  The  reagent  used  is  an  alkali  solution  of  known 
strength,  usually  a  caustic  soda  (NaOH)  solution. 

Lloyd,  an  English  chemist,  made  use  of  it  in  connection  with 
his  study  of  the  principles  and  practice  of  Cheddar  cheese- 
making  about  thirty  years  ago,  and  Mann  introduced  his  test, 
which  is  still  in  quite  common  use,  in  1890.  The  principle  of 
these  different  tests  is  the  same.  It  is  only  in  the  details  that 
they  differ. 

In  these  acidity  tests  the  acidity  of  the  milk  or  cream  is 
reduced  to  the  neutral  point,  or  the  point  where  the  substance 
tested  is  neither  acid  nor  alkaline.  This  is  true  and  complete 
neutralization. 

"  NEUTRALIZATION  "  OF  CREAM  FOR  BUTTER-MAKING 

We  now  come  to  the  use  of  the  words  "neutralization"  and 
"neutralizer"  in  a  new  sense,  in  connection  with  cream.  What 
is,  in  popular  language,  termed  the  "neutralization"  of  cream  is, 
in  reality,  merely  a  lowering  or  reduction  of  its  acidity  to  a  point 
at  which  the  cream  can  be  efficiently  pasteurized,  without  causing 
an  excessive  loss  of  fat  in  the  buttermilk.  The  substances  most 
commonly  used  for  the  purpose  of  reducing  the  acidity  are  milk 


"NEUTRALIZATION"  OF  CREAM  FOR  BUTTER-MAKING      185 

of  lime  and  soda  ash.  Neither  of  these  alkalies  should  ever  be 
used  to  reduce  the  acidity  of  cream  to  the  neutral  point,  as  in 
doing  this  there  is  grave  danger  of  injuring  the  quality  of  the 
butter  made  from  it.  The  necessity  for  reducing  the  acidily  of 
cream  came  in  with  the  general  use  of  the  little  hand  separator 
on  the  farm.  The  volume  of  cream  thus  produced  was  small; 
hence,  the  holding  of  cream  at  home  until  a  sufficient  volume 
was  accumulated  for  delivery  resulted,  in  many  cases,  in  cream 
being  delivered  in  a  very  sour  condition,  or  in  such  a  condition 
that  it  could  not  be  pasteurized  unless  the  acidity  was  reduced. 

There  is  some  dispute  as  to  who  first  used  an  alkali  for  reduc- 
ing the  acidity  of  cream  so  that  it  could  be  efficiently  pasteurized. 
We  find  that  in  1896,  Babcock  and  Russell  of  Wisconsin  issued 
Bulletin  No.  54  explaining  the  preparation  and  use  of  viscogen 
for  the  purpose  of  restoring  cream  for  city  trade  to  its  natural 
consistency,  as  in  the  process  of  heating  the  lime  salts  are  thrown 
down  and  the  cream  assumes  a  very  thin  appearance.  Viscogen 
is  composed  of  cane-sugar  and  lime.  We  are  told  that  one 
creamery  in  particular  used  viscogen  as  a  neutralizer  in  sour 
cream  at  a  very  early  date. 

As  far  back  as  1901-02,  one  of  the  authors  conducted  exten- 
sive experiments  in  the  use  of  alkalies  of  various  kinds  for 
reducing  the  acidity  of  cream;  and  in  so  far  as  he  knows  he  was 
the  first  to  take  up  experimental  work  in  reducing  the  acidity  of 
cream  for  butter-making.  Some  butter-manufacturing  firms,  as 
early  as  1905,  used  a  lime  preparation  in  the  commercial  manu- 
facture of  butter.  Since  then  the  practice  has  gradually  grown 
until  now  it  is  very  general. 

Why  do  we  neutralize  cream?  The  authors  believe  that  there 
is  an  entirely  satisfactory  answer  to  this  pertinent  question  and 
hope  to  be  able  to  show  that  modern  creamery  conditions  demand 
and  fully  justify  neutralization. 

Butter,  at  best,  is  a  perishable  product — so  much  so  that  even 
butter  of  the  best  keeping  quality  must  be  placed  in  cold  storage 
at  a  low  temperature  (close  to  o°  F.)  if  it  is  to  be  held  any  length 
of  time  and  retain  its  good  flavor.  The  souring  or  ripening  of 
cream  for  butter-making  has  been  practiced  from  time  imme- 


186  NEUTRALIZATION 

morial.  Many  farmers'  wives  have  become  so  proficient  in  the 
art  of  ripening  cream  and  the  making  of  butter  that  they  have 
gained  an  enviable  reputation  in  their  own  communities.  The 
system  of  ripening  or  souring  cream  had  been  practiced  by  the 
home  dairies  for  a  long  time  before  alkali  tests  were  used.  At 
this  early  date  it  was  the  custom  to  ripen  or  sour  the  cream  until 
it  assumed  a  thick,  granular  appearance  and  had  a  pleasant 
sour  taste.  The  flavor  that  cream  imparts  to  butter  depends 
upon  the  kind  of  organisms  that  predominate  in  it.  The  observ- 
ance of  sanitary  methods  on  the  part  of  the  producer  is  con- 
ducive to  the  presence  of  the  right  species  of  bacteria  in  the 
cream.  Cleanliness  and  sanitary  methods  should  be  observed 
by  the  makers,  whether  in  the  private  dairy  or  in  the  factory. 
This  is  one  of  the  first  requisites  of  good  butter-making;  hence, 
all  good  butter-makers,  whether  in  the  private  dairy  or  in  the 
factory,  observe  cleanliness  as  a  fast  rule.  Some  butter-makers 
have  gained  national  reputations  by  exhibiting  butter  in  state  and 
national  butter  contests,  due  to  their  ability  to  control  the  ripen- 
ing of  cream,  by  using  pure  lactic  acid  cultures  in  ripening  to  a 
certain  degree  of  acidity.  One  of  the  main  causes  of  undesirable 
flavors  in  cream  is  neglect  on  the  part  of  the  producers  to  thor- 
oughly cleanse  separators  and  other  utensils  that  come  in  con- 
tact with  the  cream  on  the  farm,  thus  allowing  undesirable 
ferments  to  gain  control.  Another  cause  is  neglect  to  cool  cream, 
immediately  after  separation,  to  a  low  temperature.  No  time 
limit  can  be  rightfully  placed  on  the  delivery  of  cream.  Some 
patrons  deliver  cream  once  or  twice  a  week,  even  during  the 
summer,  in  such  condition  that  the  highest  grade  of  butter  can 
be  manufactured  from  it,  while  others  deliver  cream  daily  and 
yet  its  flavor  is  such  that  it  is  impossible  to  make  the  finest 
quality  of  butter  from  it.  The  quality  of  butter  produced 
depends  upon  the  condition  of  the  cream  when  it  enters  the 
churn.  The  fact  that  cream  may  be  high  in  acid  when  it  reaches 
the  creamery  is  not  an  indication  that  poor  butter  will  be  made 
from  it.  If  the  acidity  of  the  cream  is  reduced  so  that  the  cream 
can  be  efficiently  pasteurized,  a  pure  lactic  acid  culture  can  be 
used  again  to  ripen  it,  as  only  a  small  portion  of  the  milk-sugar 


"NEUTRALIZATION"  OF  CREAM  FOR  BUTTER-MAKING      187 

has  been  converted  into  acid  at  the  first  souring.  A  great  deal 
of  cream  arrives  at  the  factories  in  too  sour  a  condition  to  make 
good  butter  unless  the  acidity  is  reduced.  Hence,  we  can  see  the 
necessity  of  using  a  harmless  alkali  for  reducing  the  acidity. 

The  introduction  of  the  farm  or  hand  separator  has  revolu- 
tionized the  creamery  business  in  America.  While  no  reliable 
statistics  are  available  as  to  the  number  of  separators  used  among 
the  dairymen  of  the  country,  it  is  estimated  that  90  per  cent  of  the 
butter  produced  in  the  creameries  of  the  country  is  manufactured 
from  hand  separator  cream.  The  principal  reason  for  the  gen- 
eral adoption  of  the  hand  separator  on  the  farms  by  American 
dairymen  was  that  they  were  always  able  to  get  sweet,  warm 
skim-milk  for  feeding  the  young  stock.  When  milk  was  sent  to 
the  creameries  under  the  whole-milk  system,  it  frequently  hap- 
pened through  delays  and  other  causes  that  the  skim-milk  would 
be  in  a  very  bad  condition  for  feeding  purposes  upon  its  return 
to  the  farm.  In  addition  to  this,  the  lower  cost  of  getting  butter- 
fat  to  the  creamery  in  the  form  of  cream  greatly  reduced  the 
expense.  A  can  of  cream  has  concentrated  in  it  the  fat  of  pos- 
sibly ten  or  more  cans  of  milk,  and  the  cost  per  pound  of  fat  for 
shipping  a  considerable  distance  is  small.  Consequently,  there 
have  been  established  large  creameries  equipped  with  the  most 
modern  machinery,  not  only  for  the  manufacturing  of  butter 
but  for  utilizing  the  by-products  as  well.  In  addition  to  this, 
many  such  concerns  have  cut  out  the  middleman  and  thus 
reduced  the  expenses  of  selling.  Moreover,  when  a  large  volume 
of  business  is  conducted  at  one  place,  more  skilled  labor  can  be 
employed.  These  are  some  of  the  reasons  why  the  large  or 
centralized  creamery  has  developed  so  rapidly. 

It  has  been  estimated  that  80  to  85  per  cent  of  our  butter  is 
made  from  cream  produced  by  farmers  who  are  not  dairymen 
in  the  full  sense  of  that  term.  Dairying  with  them  is  a  side  line. 
Hence,  the  volume  of  cream  produced  is  not  sufficient  to  war- 
rant its  delivery  to  the  creamery  or  buying  station  daily  or  even 
every  other  day.  This  means  that  a  large  volume  of  the  cream 
received  at  the  central  plant  is  sour  to  a  greater  or  less  degree, 
although  its  flavor  may  be  quite  clean.     When  such  cream  has 


188  NEUTRALIZATION 

been  "  neutralized  "  by  milk  of  lime  and  pasteurized,  it  can  be 
made  into  a  very  fine  quality  of  butter.  The  president  of  a  large 
creamery  company,  possibly  the  second  largest  manufacturer 
of  creamery  butter  in  this  country,  made  a  sworn  statement  that 
during  the  year  1920  they  manufactured  27  million  pounds  of 
butter  from  cream  that  had  been  separated  on  the  farms  in 
various  states  and  that  25  million  pounds  out  of  the  27  million 
pounds  sold  for  extras  or  specials,  some  of  it  selling  at  a  premium 
even  above  specials.  All  this  butter  was  made  from  cream  of 
which  the  acidity  had  been  reduced  by  milk  of  lime.  The  fact 
that  cream  can  be  shipped  a  long  distance  has  been  the  means  of 
developing  and  stimulating  dairying  in  sections  of  the  country 
where  there  was  not  enough  cream  available  to  supply  a  local 
creamery.  Where  there  is  a  sufficient  volume  of  business  to 
sustain  a  local  creamery,  and  the  same  is  rightly  managed,  no 
system  will  give  greater  returns  to  the  producer.  Whether  a 
creamery  is  local  or  centralized,  the  same  condition  prevails. 

To  make  butter  of  the  best  keeping  quality  it  is  necessary 
that  the  cream  be  pasteurized.  Local  creameries,  as  well  as  the 
large  creameries,  receive  some  very  sour  cream,  but  not  usually 
in  as  great  proportion.  If  such  cream  is  to  be  pasteurized,  it  is 
essential  that  the  acidity  be  reduced.  Investigations  conducted 
by  the  Dairy  Division  of  the  Federal  Government  and  others 
have  demonstrated  that  butter  made  from  cream  with  a  low 
acidity  possesses  better  keeping  qualities  when  placed  in  storage 
than  butter  made  from  cream  having  a  high  degree  of  acidity. 
Reducing  the  acidity  of  cream  to  the  right  point  is  a  problem 
that  necessitates  intelligent  care  and  an  understanding  of  the 
effects  of  the  use  of  an  alkali.  Cream  that  has  been  exceedingly 
high  in  acid,  which  has  been  reduced  by  lime  water  or  some  other 
harmless  alkali  substance,  cannot  be  re-ripened  with  safety  to 
the  same  degree  of  acidity  as  sweet  cream  that  has  never  had  its 
acidity  reduced.  Investigation  has  not  revealed  any  satisfactory 
explanation  of  this  fact.  It  would  seem  that  the  alkali  used  for 
reducing  the  acidity  does  not  penetrate  all  the  particles  of  cream, 
or,  in  other  words,  that  the  cream  is  not  in  a  perfectly  liquid 
condition.     Some  cream  received  at  the  factories  is  very  sour 


"NEUTRALIZATION"  OF  CREAM  FOR  BUTTER-MAKING      189 

and  lumpy.  It  may  be  that  the  solution  used  does  not  come  in 
contact  with  the  acid  encased  in  the  lumpy  cream  or  particles 
of  cream. 

To  get  the  best  results  from  neutralization,  a  large  fore- 
warmer  should  be  used  and  the  cream  heated  to  8 50  to  90 °  F., 
and  thoroughly  mixed  by  keeping  the  coil  moving  before  and 
while  adding  the  neutralizer.  The  neutralizer  should  be  dis- 
tributed as  evenly  as  possible  throughout  the  entire  mass  so 
that  it  will  come  in  contact  as  far  as  possible  with  all  particles  of 
the  cream. 

Butter  made  from  high-acid  cream,  whether  pasteurized  or 
unpasteurized,  has  a  tendency  to  develop  a  pronounced  fishy 
flavor  when  placed  in  storage.  It  is  difficult  to  pasteurize  sour 
cream  if  its  acidity  has  not  been  reduced,  as  the  heat  causes  the 
cream  to  become  stringy  or  ropy,  due  to  the  coagulation  of  the 
casein.  This  is  particularly  true  with  thin  cream.  If  the  acidity 
of  cream  is  high  and  it  is  churned  in  this  condition,  without  having 
the  acidity  reduced,  butter  made  from  it  will  invariably  be  sour. 
This  will  not  impair  its  food  value  nor  will  it  make  the  butter 
injurious  to  health,  but  it  will  impair  the  flavor.  Large  classes 
of  people  in  America  and  the  European  countries  spread  their 
bread  with  sour  cream  and  regard  it  as  a  delicacy.  The  health- 
fulness  of  buttermilk,  koumiss,  and  other  fermented  milks  is 
well  known. 

In  investigations  pursued  in  the  laboratory  of  the  American 
Association  of  Creamery  Butter  Manufacturers  on  the  heavy 
losses  of  butter-fat  in  buttermilk,  it  was  found  that  the  fat- 
globules  that  escape  in  the  churning  process  and  pass  off  in  the 
buttermilk  are  the  small  globules  which  are  encased  in  the  meshes 
of  the  casein.  The  precipitation  of  the  casein  by  heat  in  the 
process  of  pasteurization,  where  the  acidity  of  the  cream  has  not 
been  reduced,  causes  extreme  losses  in  the  buttermilk.  In  some 
instances  as  much  as  1  or  2  per  cent  of  fat  is  found  in  buttermilk 
made  from  such  cream.  Hence,  the  reduction  of  the  acidity 
for  pasteurization  is  a  necessity  from  an  economic  standpoint, 
if  for  no  other  reason. 

Sour  cream  is  a  farm  problem.     Every  creameryman  would  be 


190  NEUTRALIZATION 

pleased  to  get  cream  in  such  a  sweet  condition  that  it  would  not 
be  necessary  to  reduce  the  acidity  for  pasteurization.  The 
alkalies  most  commonly  used  for  reducing  the  acidity  of  cream 
are  limewater  and  soda  ash.  The  authors  have  never  recom- 
mended the  use  of  any  other  substance  than  limewater  or  milk 
of  lime.  The  amount  of  lime  used  in  reducing  the  acidity,  some- 
what less  than  one-tenth  of  i  per  cent,  is  so  infinitesimal  that 
it  passes  off  in  the  buttermilk  and  has  no  effect  upon  the  butter. 
The  fat-globules  of  milk  being  coated  with  a  film,  the  alkali 
solution  used  for  reducing  the  acidity  is  mixed  with  the  serum 
or  the  other  component  parts  of  cream  rather  than  the  butter-fat ; 
hence,  the  small  per  cent  of  lime  used  practically  all  passes  off 
with  the  buttermilk.  p 

Investigations  pursued  under  the  direction  of  one  of  the 
authors  showed  that  butter  made  from  cream  of  which  the 
acidity  had  been  reduced  by  milk  of  lime  did  not  contain  any 
more  lime  than  butter  made  from  whole  milk  to  which  no  lime 
had  been  added,  and  contained  less  lime  than  a  number  of 
samples  of  dairy  or  farm  butter.  Investigations  of  this  butter 
were  made  at  the  Universities  of  Wisconsin,  Cornell  and  Purdue. 
The  explanation  of  the  higher  percentage  of  lime  in  dairy  butter 
may  possibly  be  that  the  cream  for  the  farm  butter  was  churned 
at  a  higher  temperature  than  the  cream  from  which  the  butter  in 
the  creameries  was  made.  Butter  churned  at  a  high  temperature 
will  invariably  contain  a  high  percentage  of  casein.  In  such 
butter  the  lime  will  be  held  between  the  meshes  of  the  casein; 
hence  the  high  percentage  of  lime  found  in  dairy  butter,  where  no 
lime  had  been  added  to  the  cream,  was  undoubtedly  due  to  the 
high  temperature  at  which  the  cream  was  churned.  Butter 
made  from  cream  which  has  been  subjected  to  reduction  of 
acidity  and  pasteurization  seems  to  give  good  satisfaction  in  the 
markets.  This  is  particularly  true  during  the  storage  season. 
Such  butter  is  then  sought  by  dealers  in  storage  butter,  owing  to 
its  excellent  keeping  qualities. 

The  use  of  limewater  in  milk  is  of  long  standing  and  well 
known.  Lime  is  an  essential  constituent  of  dairy  products.  It 
is  there  to  build  the  bones  and  to  serve  other  essential  physio- 


"NEUTRALIZATION"  OF  CREAM  FOR  BUTTER-MAKING     191 

logical  purposes.  Lack  of  lime  causes  not  only  rickets  in  the 
young,  but  also  serious  physiological  disorders  in  the  adult. 
Some  physiologists  urge  the  addition  of  lime  to  the  diet^  Its 
importance  is  thus  expressed  by  Dr.  Sherman  of  Columbia 
University  ■ 

"  Calcium  is  present  in  still  greater  abundance.  Milk  con- 
tains slightly  more  calcium,  volume  for  volume,  than  does  lime 
water.  As  a  rule  the  calcium  content  of  the  diet  depends  mainly 
upon  the  amount  of  milk  consumed.  In  family  dietaries  where 
ordinary  quantities  of  milk  are  used,  the  milk  is  apt  to  furnish 
about  two-thirds  of  the  total  calcium  of  the  diet.  Without  milk, 
it  is  unlikely  that  the  diet  will  be  as  rich  in  calcium  as  is  desirable 
either  for  the  child  or  for  the  adult." 

In  their  recent  Circular,  No.  n,  the  United  States  Depart- 
ment of  Agriculture  and  the  United  States  Food  Administration 
state  their  conception  of  the  need  of  lime  as  follows : 

"  Milk  gives  your  children  lime  and  other  salts  which  they 
need.  There  must  be  plenty  of  lime  in  their  food,  for  a  great 
deal  of  it  is  needed  for  their  bones  and  teeth  and  a  little  for  their 
blood  and  all  other  parts  of  their  bodies.  Right  food,  not  drugs, 
is  what  children  need.  Big  boys  and  girls  and  grown  people, 
as  well  as  children,  need  lime,  because  the  bones  are  constantly 
wearing  away  little  by  little  and  must  be  replaced." 

Milk  is  the  chief  food  for  lime.  It  is  much  richer  in  it  than 
other  common  foods.  These  lines  stand  for  lime,  the  top  one  for 
the  lime  in  a  cup  of  milk,  the  others  for  the  lime  in  a  serving  of 
some  other  foods.  Notice  how  much  more  there  is  in  milk  than 
in  the  others." 


AMOUNT  OF  LIME  IN 


i  cup  of  milk 


^  cup  of  carrots 


i  egg 


2  slices  of  bread 


192 


NEUTRALIZATION 


THE  PREPARATION  AND  USE  OF  LIME  AS  A  NEUTRALIZER 

While  there  are  other  preparations,  as  those  of  the  sodas, 
which  are  sometimes  used  for  the  neutralization  of  cream,  the 
present  discussion  will  be  limited  to  the  preparation  and  use  of 
lime  compounds  as  neutralizers. 

Before  proceeding  with  this,  however,  the  authors  would 
digress  a  little  to  give  the  results  of  analyses  made  of  different 
samples  of  lime  in  the  laboratory  of  the  American  Association  of 
Creamery  Butter  Manufacturers.  Eleven  samples  of  lime  from 
various  parts  of  the  United  States  were  analyzed  to  ascertain 
their  fitness  for  reducing  the  acidity  of  cream.  The  solubility 
of  the  limes  in  a  0.7  per  cent  lactic  acid  solution  and  their  neu- 
tralizing power  in  terms  of  lactic  acid  were  determined*  The 
investigators  were  surprised  to  find  that  this  amount  of  chemical 
work  revealed  very  little  more  than  was  evident  to  the  senses, 
aided  by  common  sense.     Here  fojlow  a  few  typical  exhibits: 


Silica 

Volatile, 

Iron  and 

Mag- 
nesium 
Oxide 

No. 

Kind 

Quality 

(Sand), 
Per 

Per 

Clay, 
Per 

Calcium 
Oxide 

Total 

Cent 

Cent 

Cent 

4 

Hydrated 

Good 

0.31 

n-45 

o.73 

88.60 

0 

100.00 

11 

Quick 

Good 

0.  26 

4-75 

1.56 

93  40 

0 

99-97 

6 

Quick 

Good 

0.36 

7.00 

1-25 

58.20 

33-54 

100.35 

3 

Quick 

Poor 

2-43 

i-35 

6.44 

55-4Q 

34- 19 

99.81 

No.  n  is  a  high  calcium  lime.  Nos.  3  and  6  are  magnesian 
limes.  Although  the  percentages  of  calcium  in  11  and  3  differ 
widely,  they  both  give  good  results  in  reducing  acidity.  Mag- 
nesia acts  like  lime  and  is  not  as  much  inclined  as  lime  to  flavor 
the  butter.  It  has  a  greater  neutralizing  power  than  calcium. 
No.  3  contained  too  much  silica  (sand),  clay  and  iron.  This 
was  just  as  discernible  by  a  physical  inspection  as  by  chemical 
analysis.  The  sand  could  be  seen  and  felt  and  the  clay  made  a 
granular  yellow  mixture. 

There  are  two  forms  of  lime  that  are  used  in  the  preparation 
of  neutralize^  namely,  quicklime  in  lump  or  in  powder  form,  and 
hydra  teft  lime,  which  is  quicklime  slaked  by  the  lime-maker 


THE  PREPARATION  AND  USE  OF  LIME  AS  A  NEUTRALIZER     193 

instead  of  the  user.  As  is  shown  below,  it  takes  74  pounds  of 
completely  hydrated  lime  to  equal  56  pounds  of  quicklime  for 
neutralizing  purposes.  Of  course,  the  hydration  is  often  only 
partial  and  then  the  difference  is  not  so  great. 

It  is  really  a  lime  mixture  in  the  form  of  milk  of  lime,  and  not 
limewater,  that  is  used,  as  lime  is  only  soluble  to  a  very  small 
extent  in  water,  and  it  would  require  too  much  of  this  to  make  its 
use  practicable. 

Lime  should  be  free  of  such  impurities  as  sand,  clay  and  iron, 
and  the  lime  preparations  offered  by  responsible  firms  for  neu- 
tralizing purposes  usually  are. 

It  is  very  important  that  the  lime  mixture  be  properly  pre- 
pared. Much  more  trouble  arises  from  improper  preparation 
than  from  defects  in  the  lime  itself. 

Quicklime  is  obtainable  in  powder  form,  packed  in  tin  canis- 
ters. This  form  gives  excellent  satisfaction,  as  the  quicklime  is 
clean,  uniform  and  free  of  waste  material,  and  keeps  until  it  is 
all  used;  whereas  in  lump  lime  there  is  considerable  waste, 
through  air  slaking  and  the  rejection  of  unsuitable  lumps. 

A  very  suitable  mixture  is  made  up  in  the  proportion  of  17 
pounds  of  water  to  3  pounds  of  quick  lime.  The  water  should  be 
as  near  boiling  as  possible  and  the  lime  should  be  added  to  the  water 
and  not  the  water  to  the  lime.  The  lime  should  be  added  in  four 
installments  instead  of  all  at  once,  and  the  mixture  stirred  thor- 
oughly after  each  addition  of  lime.  If  properly  prepared  the 
mixture  will  be  very  smooth  and  free  of  visible  lime  particles. 
When  cool,  it  may  be  tested  by  putting  the  hand  or  a  smooth 
butter  spade  into  it  and  withdrawing.  If  smooth,  showing  no 
lime  particles,  it  is  a  good  mixture;  if  it  shows  a  very  few  par- 
ticles, it  is  fair;  and  if  it  shows  many  particles  it  is  a  poor  mixture 
and  is  more  likely  to  impart  a  limy  taste  than  is  a  smooth  mix- 
ture. A  good  mixture  properly  added  to  and  mixed  with  the 
cream,  and  not  in  excess,  is  not  nearly  so  likely  to  impart  a  limy 
taste  to  the  butter. 

A  mixture  of  3  pounds  of  lime  to  17  pounds  of  water  is  the 
same  as  15  pounds  of  lime  to  85  pounds  of  water,  or  a  15  per  cent 
mixture. 


194 


NEUTRALIZATION 


Whether  one  proceeds  scientifically  or  mechanically  in  the 
preparation  of  his  lime  mixture,  his  work  is  based  upon  the  fol- 
lowing: 

Molecular  weight  of  quicklime,  CaO,  is  40+16  =  56. 
Molecular  weight  of  hydrated,  Ca(OH)2,  is^4o+2(i6+i)  =74. 
Molecular  weight  of  lactic  acid,  C3HGO3,  is 

(3Xi2N)+6  +  (3Xi6)=9o. 

But  the  limes  are  bivalent.  Hence  56  pounds  of  quicklime 
or  74  pounds  of  slaked  lime  will  neutralize  twice  90,  or  180  pounds 
of  lactic  acid. 

Hence  1  pound  of  lactic  acid  is  neutralized  by  ^  =  .3111 
pound  quicklime. 

It  takes  2.074  pounds  of  a  15-per  cent  mixture  of  quicklime  to 
supply  .3111  pound  of  quicklime.  Hence  2.074  pounds  of  the 
quicklime  mixture  will  neutralize  1  pound  of  lactic  acid,  or  reduce 
the  acidity  of  1000  pounds  of  cream  0.1  per  cent;  and  it  is  upon 
this  figure,  which  is  theoretically  correct,  that  the  following  table 
is  based: 

TO  REDUCE  THE  ACIDITY  OF   CREAM  TO    .25    PERCENT 


Initial  Acidity  of  Cream 

Cream 
(Pounds) 

.30     .35     .40     .45     .50     .55     .60    .65  .70  .75  .80  .85  .90  .95 

Pounds  of  15  Per  Cent  Lime  Mixture  Needed 

100 

.1 

.2 

•3 

•4 

•5 

.6 

•7 

.8 

•9 

1.0 

1.1 

1.2 

i-3 

... 

500 

•5 

1.0 

1.6 

2.1 

2.6 

3-i 

3-6 

4.1 

4-7 

5-2 

5-7 

6.2 

6 

7 

7 

3 

1000 

1.0 

2.1 

3-i 

4-i 

5-2 

6.2 

7-3 

8-3 

9-3 

10.4 

11. 4 

12.4U3 

4 

14 

5 

1500 

1.5 

3-i 

4-7 

6.2 

7.8 

9-3 

10.9 

12.4 

14.0 

15.6 

17.  2 

18.7  20 

2 

21 

8 

2000 

2. 1 

4-i 

6.2 

8-3 

10.4 

12.5 

14.5  16.6 

18.7 

20.7 

22.8  24.9I27 

0 

29 

0 

2500 

2.6 

5-2 

7-8 

10.4 

130 

IS- 6 

18.120. 7 

23-3 

259 

28.5I31.1 

33 

7 

36 

3 

3000 

31 

6.2 

9-3 

12.4 

15-5 

18.7 

21.8,24.9 

28.0 

311 

34-2j37-3 

40 

4 

43 

6 

35oo 

3-6 

7.2 

10.9 

14-5 

18. 1 

21.8 

25.429.0 

32.7 

36.3 

39-9J43-6 

47 

2 

50 

8 

4000 

4.1 

8-3 

12.4 

16.6 

20.7 

24.9 

29.033.2 

37-4 

4i-5 

45.7j49.8|53 

9 

58 

1 

4500 

4.6 

9-3 

14.0 

18.7 

23-3 

28.0 

32-  737-3 

42.0 

46.7 

51.3I56.0J60 

6 

65 

3 

5000 

5-2 

10.4 

15.6 

20.7 

25-9 

3I-1 

36.3141s 

46.7 

51-8 

57.062.2:67 

4 

72 

6 

5500 

5-7 

11. 4 

17-2 

22.8 

28.5 

34-2 

39- 9145 -6 

5i.3 

57.o 

62.7^68.4,74 

1 

79 

0 

6000 

6.2 

12.4 

18.7 

24.9 

311 

37-3 

43-049-8 

56.0 

62.2 

68.4I74.7  80 

9 

87 

1 

6500 

6.7 

135 

20.3 

27.0 

33-7 

40.4 

47-253-9 

60.7 

67.4 

74. 1180.9 

87 

6 

94 

4 

7000 

7-3 

14-5 

21.8 

29.0 

36.3 

43-6 

50.8 

58.1 

65-4 

72.6 

79.987.1 

04 

< 

101 

6 

THE  PREPARATION  AND  USE  OF  LIME  AS  A  NEUTRALIZER    195 

The  common  practice  in  creamery  work  is  to  measure  the 
lime  mixture,  in  adding  it  to  the  cream,  instead  of  weighing  it.  In 
case  this  is  done  the  mixture  should  be  made  up  so  that  there 
will  be  12.5  pounds  of  quicklime  in  10  gallons  of  the  mix,  that  is, 
this  quantity  of  lime  should  be  mixed  with  about  8  gallons  of  hot 
water  and  then  brought  up  to  10  gallons  by  adding  sufficient  hot 
water.  This  water  to  be  added  should  be  heated  in  an  open  vessel 
so  as  to  drive  off  any  carbonic  acid  gas  there  may  be  in  it,  and 
should  not  be  added  directly  from  a  hose  or  tap. 

In  10  gallons  of  the  mixture  there  are  12.5  pounds  lime. 

12 .  c 
In  1  quart  of  the  mixture  there  is  — —  =  .3125  pound  lime. 

40 

We  have    already  shown    that  .3111  pound  quicklime  will 

reduce  the  acidity  of  1000  pounds  cream  .1  per  cent.     Hence,  1 

quart  of  the  lime  mixture,  which  contains  .3125  pound  quicklime, 

.lX.^I2's 

will  reduce  the  acidity  of  1000  pounds  cream : -  =  .1004 

.3111 

per  cent  =  .1  per  cent  practically.     Or,  1  pint  of  the  lime  mixture 

will  reduce  the  acidity  of  1000  pounds  cream  .05  per  cent.     It 

is  upon  these  figures  that  the  table  on  page  196  is  based. 

How  many  pints  of  lime  mixture  will  it  take  to  reduce  the 
acidity  of  3400  pounds  of  cream  from  .70  to  .25  per  cent?  In  the 
column  under  .70  and  opposite  3400,  this  is  given  as  30.5  pints. 
The  same  quantity  of  lime  mixture  would  be  used  for  all  acidities 
nearer  to  .70  per  cent  than  either  .65  per  cent  or  .75  per  cent. 
This  principle  applies  all  through  the  table. 

Note  the  simple  numbers  opposite  1000  pounds  of  cream. 
The  quantity  of  mixture  required  for  any  weight  of  cream  can  be 
quickly  determined  by  multiplying  the  weight  of  cream  by  the 
amount  of  mixture  required  to  reduce  the  acidity  of  1000  pounds 
of  cream  to  .25  per  cent  and  dividing  by  1000  (or  pointing  off 
three  decimal  places) .     Example : 

How  many  pints  of  lime  mixture  will  be  required  to  reduce  the 
acidity  of  6300  pounds  of  cream  from  .80  per  cent  to  .25  per  cent? 

1000  pounds  of  cream  require  1 1  pints  of  mixture. 

6300  pounds  of  cream  require  11 X  6.300  =  69.3  =69.5  pints  of 
mixture. 


196 


NEUTRALIZATION 


PINTS   OF   LIME   MIXTURE   REQUIRED   TO   REDUCE   ACIDITY  TO 

.25  PER  CENT 


Per  Cent  of  Acid  in  Cream 

Lbs.  of 
Cream 

•  30 

•35 

.40 

•45 

•5o 

•55 

.60 

•65 

.70 

•75 

.80 

.85 

.90 

■95 

1. 00 

IOO 

•  5 

•5 

•5 

•5 

•5 

1 .0 

1.0 

1 .0 

1 .0 

1 .0 

i-5 

1-5 

i-5 

200 

•5 

•5 

1 .0 

1.0!  1.0 

i-5 

i-5 

2.0 

2.0 

2.0 

2-5 

2-5 

3.0 

3-o 

300 

•5 

•5 

1.0 

1 .0 

1. 51   2.0 

2.0 

2-5 

2-5 

3-0 

3-5 

3-5 

4.0 

4.0 

4-5 

400 

•5 

1 .0 

1 .0 

i-5 

2.0    2.5 

3° 

3-o 

3-5 

4.0 

4-5 

5-o 

5-o 

5-5 

6.0 

500 

•5 

1.0 

i-5j  2.0 

2-5 

3-o 

3-5 

4.0 

4-5 

5-o 

5-5 

6.0 

6-5 

7.0 

7-5 

600 

•5 

1.0 

2.0 

2-5 

30 

3-5 

4.0 

5-o 

5-5 

6.0 

6-5 

7.0 

8.0 

8-5 

9.0 

700 

•5 

i-5 

2.0 

3-o 

3-5 

4.0 

5-o 

5-5 

6-5 

7.0 

7-5 

8-5 

9.0 

10. 0 

IO-5 

800 

1.0 

i-5 

2-5 

3-° 

4.0 

5-o 

1-5 

6-5 

7.0 

8.0 

9.0 

9-5 

10.5 

11. 0 

12.0 

900 

1.0 

2.0 

2-5 

3-5 

4-5 

5-5 

6-5 

7.0 

8.0 

9.0 

10. 0 

11. 0 

11 -5 

I2-5 

J3-5 

1000 

1 .0 

2.0 

30 

4.0 

5-o 

6.0 

7-o 

8.0 

9.0 

10. 0 

11. 0 

12.0 

130 

14.0 

15.0 

I  IOO 

1.0 

2.0 

35 

4-5 

5-5 

6-5 

7-5 

9.0 

10. 0 

11. 0 

12.0 

130 

H-5 

155 

16.5 

1200 

1.0 

2-5 

3-5 

SO 

6.0 

7.0 

8-5 

9-5 

11 .0 

12.0 

13.0 

x4-5 

J5-5 

17.0 

18.0 

1300 

i-5 

2.5 

4.0 

5-o 

6-5 

8.0 

90 

10.5 

H-5 

130 

H-5 

J5-5 

170 

18..0 

195 

1400 

i-5 

30 

4.0 

5-5 

7.0 

8-5 

10. 0 

11. 0 

12.5 

14.0 

x5.5 

17.0 

18.0 

19*5  21.0 

1500 

i-5 

30 

4-5 

6.0 

7-5 

9.0 

!°-5 

12.0 

J3-5 

15  0 

16.5 

18.0 

J9-5 

21.0 

22.5 

1600 

i-5 

30 

5-o 

6-5 

8.0 

9-5 

11. 0 

13.0 

M-5 

16.0 

17.5 

19.0 

21.0 

22.5 

24.0 

1700 

i-5 

3.5 

5-o 

7.0 

8-5 

10. 0 

12.0 

»3-5 

15-5 

17.0 

18.5 

20.5 

22.0 

24.0 

25-5 

1800 

2.0 

3-5 

5-5 

7.0 

9.0 

11. 0 

I2-5 

x4-5 

16.0 

18.0 

20.0 

215 

23-5 

25.0 

27.0 

1900 

2.0 

4.0 

5-5 

7-5 

9-5 

"5 

!3-5 

15.0 

17.0 

19.0 

21.0 

23-0 

24.5 

26.5 

28.5 

2000 

2.0 

4.0 

6.0 

8.0 

10. 0 

12.0 

14.0 

16.0 

18.0 

20.  c 

22.0 

24.0 

26.0 

28.0 

30.0 

2100 

2.0 

4.0 

6-5 

8-5 

i©-5 

12 -5 

J4-5 

17.0 

19.0 

21.0 

23.0 

25-0 

27-5 

29-5 

3i.5 

2200 

2.0 

4-5 

6-5 

9.0 

11. 0 

130 

*5-5 

r7.5 

20.0 

22.0 

24.0 

26.5 

28.5 

310 

33.o 

2300 

2-5 

4-5 

7.0 

9.0 

"5 

14.0 

16.0 

18.5 

20.5 

23  0 

25-5 

27.5 

30.0 

32.0 

34-5 

2400 

2-5 

50 

7.0 

9-5 

12.0 

14-5 

17-0 

19.0 

215 

24.0 

26.5 

29.0 

31.0 

33-5 

36.0 

2500 

2-5 

5-o 

7-5 

10. 0 

!2-5 

15.0 

J7-5 

20.0 

22.5 

25.0 

27-5 

30.0 

32.5 

35o 

37-5 

2600 

2-5 

5-o 

8.0 

10.5 

I30 

J5-5 

18.0 

21.0 

235 

26.0 

28.5 

310 

34  0 

36.5 

39-0 

2700 

2.5 

5-5 

8.0 

11 .0 

J3-5 

16.0 

19.0 

21.5 

24.5 

27.0 

29-5 

32.5 

35-o 

38.0 

40.5 

2800 

30 

5-5 

8-5 

11. 0 

14.0 

17.0 

19-5 

22.5 

25-0 

28.0 

31.0 

33-5 

36.5 

39o 

42.0 

2900 

3-o 

6.0 

8-5 

"•5 

*45 

J7-5 

20.5 

230 

26.0 

29.0 

32.0 

35-o 

37-5 

40.5 

43-5 

3000 

3.o 

6.0 

9.0 

12.0 

15.0 

18.0 

21.0 

24.0 

27.0 

30.0 

33-o 

36.0 

39o 

42.0 

45  0 

3100 

3-o 

6.0 

9-5 

!2-5 

15-5 

18.5 

215 

25-0 

28.0 

31.0 

34-o 

37.o 

4o -5 

43-5 

46.5 

3200 

3-o 

6-5 

9-5 

I30 

16.0 

190 

22.5 

25-5 

29.0 

32.0 

35-0 

38.5 

4i-5 

45- c 

48.0 

3300 

3-5 

6-5 

10. 0 

I30 

16.5  20.0 

23.0 

26.5 

295 

330 

36.5 

39-5 

43 -o 

46.0 

49-5 

3400 

3-5 

7.0 

10. 0 

J3-5 

17.0 

20.5 

24.0 

27.0 

30.5 

34 -o 

37-5 

41. 0 

44- 0 

47-5 

510 

3500 

3-5 

7.0 

10.5  14.0 

J7-5 

21.0 

24.5 

28.0 

315 

35.o 

38.5 

42.0 

45-5 

49.o 

52.5 

3600 

3.5 

7.0 

XI.  014-5 

18. 021. 5 

25.0 

29.0 

32.5 

36.0 

39-5 

43 -o 

47-c 

5o.5 

54-0 

3700 

3-5 

7-5 

11.0I15.0 

18.5 

22.0 

26.0 

29-5 

33-5 

37 -o 

40.5 

44-5 

48.052.0 

55-5 

3800 

4.0 

7-5 

11.5X5.6 

19.0 

23-0 

26.5 

30.5 

34  0 

38.0 

42.0 

45-5 

49-5j53-o 

57.o 

3900 

4.0 

8.0 

"•5I5.5 

19-5 

23-5 

27.5 

310 

350 

39  0 

43 -o 

47-0 

50.554.5 

58.5 

4000 

4.0 

8.0 

i2.o{i6.o 

20.0 

24.0 

28.0 

32.036.0 

40.0 

44-o 

48.0 

52.0 

56.0 

60.0 

4100 

4.0 

8.0 

!2-5 

16.5 

20.5 

24-5 

28.5 

33 -o 

37.o 

41.0 

45-o 

49 -o 

S3- 5 

57-5 

61.5 

4200 

4.0 

8-5 

12.5 

17.0 

21.0 

25.0 

295 

33-5 

38.0 

42.0 

46.0 

50.5 

54-5 

59  0 

63.0 

4300 

45 

8-5 

I30 

17.0 

21.5 

26.0 

300 

34-5 

38.5 

43 -o 

47-5 

51-5 

56.0 

60.0 

64-5 

4400 

4.5 

9.0 

I3.O 

17-5 

22.0 

26.5 

310 

35  0 

39-5 

44- 0 

48.5 

53 -o 

57.061.5 

66.0 

45;  00 

4-5 

9.0 

13-5 

18.0 

22.5 

27.0 

3i-5 

36.0 

40.5 

45 -o 

49-5 

54 -o 

58.51630 

67-5 

4600 

4-5 

9.0 

I4.O 

18. s 

23.0 

27-5 

32.0 

37.o 

41-5 

46.0 

50.5 

55-o 

60.0 

64- 5 

69.0 

4700 

4-5 

9-5 

I4.O 

19.0 

23 -5 

28.0 

33  0 

37-5 

42.5 

47-o 

5i-5 

56.5 

61.0 

66.0 

70.5 

4800 

5-o 

95 

14-5 

19.0 

24.0 

29.0 

33-538.5 

43o 

48.0 

53-0 

57-5 

62.5 

67.0 

72.0 

4900 

5-o 

10. 0 

14-5  19-5 

24-5 

29-5 

34-539-Q 

44-0 

49.0 

54-0 

59.0 

63 -5 

68.5 

73-5 

5000 

5-o 

10. 0 

15.0  20.0 

25.0 

30.0 

35.040.0 

45  0 

50.0 

55-o 

60.0 

65.0 

70.0 

75-o 

6000 

6.0 

12.0 

18.0J24.0 

30.0 

36.0 

42.0  48.0 

54  0 

60.  c 

66.0 

72.0 

78.0 

84.0 

90.0 

THE  PREPARATION  AND  USE  OF  LIME  AS  A  NEUTRALIZER     197 

This  is  a  general  solution  which  applies  to  any  weight  of 
cream. 

Where  lime  is  completely  slaked  or  hydrated  it  takes  a  little 
over  32  per  cent  more  of  it  than  of  quicklime  (74  pounds  as  against 
56  pounds)  to  make  the  same  strength  of  mixture.  As  the  mix- 
ture upon  which  the  table  (p.  196)  is  based  contains  12.5  pounds  of 
quicklime  to  10  gallons,  it  would  require  16.5  pounds  of  hydrated 
lime  to  10  gallons  to  make  the  same  strength  of  mixture.  If 
the  lime  is  only  partially  slaked  it  will,  of  course,  take  less  than 
16.5  pounds. 

The  quantities  of  lime  indicated  for  making  the  mixture  are 
theoretically  correct,  but  the  individual  user  will  be  obliged  to 
determine  by  test  whether  the  mixture  is  right  in  strength  for  his 
cream.  It  may  be  necessary  to  use  a  little  more  or  a  little  less 
lime  than  indicated,  in  making  the  mixture,  probably  a  little  less 
if  any  change  has  to  be  made.  If  necessary,  a  slight  change  may 
be  made  in  the  strength  of  the  mixture  to  avoid  changing  the 
table. 

In  investigations  conducted  by  Hunziker,  in  which  he  used 
the  strength  and  quantity  of  lime  mixture  supposed  to  be  suf- 
ficient to  reduce  the  acidity  of  the  cream  to  .25  per  cent,  he 
secured  the  following  average  results: 

Per  Cent 

Initial  acidity  of  cream 75 

Acidity  three  hrs.  after  neutralizing,  pasteurizing  and  cooling.   .  3$ 

In  other  words,  whereas  the  acidity  should  have  been  reduced 
by  .50  per  cent  (.75  — .25)  it  was  only  reduced  by  .42  per  cent 
(•75 --33)-  This  means  that  (33  —  25)^-50  or  58o  =  i6  per  cent 
of  the  neutralizer  was  not  used,  or  that  this  mixture  would  need 
to  be  strengthened  to  the  extent  of  the  addition  of  15  to  20  per 
cent  more  lime. 

On  the  other  hand,  Hunziker  found  that  when  enough  lime 
mixture  was  added  to  a  pure  lactic  acid  solution  to  theoretically 
reduce  its  acidity  to  .25  per  cent  it  actually  did  reduce  it  to  this 
point.  The  conclusion  he  reached,  through  his  investigations, 
was  that  some  of  the  lime  added  to  cream  attaches  itself  to  the 


198  NEUTRALIZATION 

casein  and  therefore  all  of  it  is  not  used  up  in  the  neutralization 
of  the  lactic  acid  in  the  cream. 

The  strength  of  a  milk  of  lime  mixture  can  be  increased  in 
either  of  two  ways,  (a)  through  the  use  of  a  larger  proportion  of 
lime,  (b)  through  the  use  of  lime  containing  a  larger  proportion  of 
magnesium  oxide,  which  is  stronger,  pound  for  pound,  than 
calcium  oxide. 

When  a  lime  mixture  is  made  up  in  small  quantities,  a  ten- 
gallon  can  will  suffice  for  this  purpose.  But  where  larger  quan- 
tities are  required  a  cylinder-shaped  tank  similar  to  a  starter 
tank,  with  an  agitator  in  it,  should  be  used.  This  can  be  of  any 
suitable  capacity,  say  ioo  to  200  gallons.  A  simple  gage  may  be 
used  for  measuring  the  contents.  The  user  must  remember  that 
he  is  dealing  with  a  mixture  and  not  a  solution,  and  that  not 
only  must  there  be  a  thorough  agitation  at  the  time  the  mix- 
ture is  made  but  this  must  be  repeated,  to  a  lesser  degree,  when- 
ever any  of  the  mixture  is  used,  as  the  lime  settles. 

Although  the  best  limes  do  not  contain  100  per  cent  calcium 
oxide,  they  usually  contain  enough  magnesium  oxide,  which  is 
stronger  pound  for  pound  than  calcium  oxide,  to  make  up  for  this 
shortage. 

There  are  some  points  that  should  be  kept  carefully  in  mind 
in  the  preparation  and  use  of  neutralizers. 

The  lime  does  not  act  so  quickly  and  completely  that  its  full 
effect  is  secured  immediately.  For  this  and  other  reasons,  the 
acidity  of  the  cream  after  pasteurization  is  lower  than  it  was 
before  pasteurization.  The  amount  of  drop  in  acidity  varies 
with  the  cream,  lime  mixture  and  locality. 

Some  creameries  add  the  lime  mixture  directly  to  the  cans  of 
cream.  Some  run  it  by  a  faucet  into  either  the  dump  vat  or  the 
pasteurizer.  Others  fill  a  supply  vat  or  forewarmer  and  then 
reduce  the  acidity  to  the  desired  point.  The  last  method  is  the 
best. 

The  authors  believe  there  is  yet  considerable  to  be  learned 
about  methods  of  applying  neutralizer  to  cream  in  order  to 
secure  the  best  results  and  avoid  unnecessary  losses  of  fat  in  the 
buttermilk. 


THE  PREPARATION  AND  USE  OF  LIME  AS  A  NEUTRAL1ZER     199 

A  careful  determination  of  the  acidity  of  the  cream  should 
always  be  made  both  before  adding  the  neutralizer  and  after  it  is 
pasteurized  and  cooled.  It  may  be  found  necessary  to  reduce  the 
acidity  of  the  cream  a  little  more,  or  on  the  other  hand  it  may  be 
found  that  the  acidity  of  the  cream  is  being  reduced  too 
much.  This  determination  will  thus  act  as  a  guide  for  future 
work. 

If  the  cream  is  to  be  ripened  again  the  acidity  is  usually 
reduced  to  0.15  per  cent  to  .22  per  cent  (90  to  120  Mann's)  and 
then  ripened  to  the  desired  acidity. 

Some  prefer  the  use  of  slaked  or  hydra  ted  lime.  While  hot 
water  must  be  used  in  the  preparation  of  the  quicklime  mixture, 
the  hydrated  lime  should  always  be  mixed  with  cold  water. 

OTHER  NEUTRALIZERS 

Some  creameries  use  carbonate  and  bicarbonate  of  soda — 
commonly  spoken  of  as  soda  ash — as  neutralizers.  The  soda 
ash  is  very  soluble  in  water  and  forms  a  clear  liquid  solution. 
This  is  more  easily  made  and  added  to  the  cream  than  is  the  lime 
mixture,  and  doubtless  this  is  the  main  reason  for  its  use. 

What  has  already  been  said  indicates  the  authors'  preference 
for  the  use  of  lime  as  a  neutralizer  and  the  reasons  for  this 
preference.  The  following  points  may  therefore  be  treated 
briefly : 

Lime  is  something  that  is  well  known  and  generally  regarded 
as  clean  and  wholesome,  and  the  use  of  it  in  the  neutralization  of 
cream  will  not  offend,  in  the  slightest  degree,  the  susceptibilities 
of  the  most  fastidious. 

Attention  is  frequently  drawn,  by  physiologists,  physicians 
and  students  of  die ti tics,  to  the  necessity  for  a  liberal  supply  of 
lime  in  the  diet  of  children  and  adults,  and  to  the  fact  that  in 
many  foods  there  is  a  shortage  of  this  constituent. 

Limewater  is  commonly  used  as  an  accessory  to  and  a  cor- 
rective of  the  foods  of  hospital  patients  and  of  children  and 
infants. 

While  it  is  true,  as  has  already  been  pointed  out,  that  the 


200  NEUTRALIZATION 

lime  used  in  the  cream  passes  off  in  the  buttermilk,  yet  it  is 
important  that  the  consumer  feel  assured  that  the  substance 
used  as  a  neutralizer  is  something  which  is  not  foreign  to  milk, 
cream  and  butter  and  is  wholesome,  and  to  which  no  objection 
can  be  taken. 


CHAPTER  XV 
PASTEURIZATION 

Definition. — As  applied  to  butter-making  and  city  milk,  pas- 
teurization may  be  denned  as  a  process  of  heating  milk  or  cream 
to  a  temperature  sufficiently  high  to  destroy  the  great  majority 
of  the  bacteria  and  other  ferments  contained  therein  and.  cooling 
it  quickly  to  a  low  temperature.  The  name  is  derived  from 
Louis  Pasteur,  an  eminent  French  scientist,  who  made  the  dis- 
covery in  the  years  1860-64,  that  if  wines  were  heated  to  a  certain 
temperature  (700  C.  or  1580  F.),  and  cooled  again,  fermentation 
would  stop. 

In  1884  Soxhlet  applied  the  method  of  heating  to  milk  for 
destroying  bacteria. 

Storch  Test  for  Pasteurization. — S torch,  at  the  Royal 
Agricultural  Experiment  Station,  Copenhagen,  Denmark,  was 
the  first  to  apply  general  pasteurization  to  cream  for  butter- 
making.  Denmark  has  a  law  making  pasteurization  com- 
pulsory. This  law  was  enacted  to  prevent  the  spread  of  tuber- 
culosis among  the  herds.  The  law  requires  that  milk  or  cream 
must  be  heated  to  8o°  C,  or  1760  F.  Samples  of  skim-milk  from 
the  creameries  are  required  to  be  sent  to  the  Experiment  Station 
where  they  are  tested  by  the  Storch  test  to  ascertain  if  creameries 
are  complying  with  the  requirements  of  the  law. 

Storch  found  that  of  all  the  reagents  that  might  be  used  for 
determining  whether  milk  or  cream  had  been  heated  to  80 °  C.  or 
1760  F.,  the  best  was  paraphenylene  diamine.  This  compound 
ordinarily  gives  a  brown  color  when  acted  upon  by  u  active  " 
oxygen,  but  in  the  presence  of  casein  in  milk  the  color  is  a  beau- 
tiful indigo  blue. 

To  carry  out  the  test  about  5  c.c.  of  milk  or  cream  are  put 

201 


202  PASTEURIZATION 

into  a  test-tube  and  one  or  two  drops  of  a  0.2  per  cent  solution  of 
hydrogen  peroxide  is  added  from  a  dropping  bottle,  also  two 
drops  of  a  2  per  cent  solution  of  paraphenylene  diamine,  from  a 
dropping  bottle.  Brown  dropping  bottles  should  be  used  to 
prevent  the  light  from  weakening  the  reagents.  The  test-tube 
is  then  well  shaken,  and  if  the  milk  has  not  been  heated  above 
780  C,  or  1720  F.,  or  if  not  heated  at  all,  an  intense  blue  coloration 
is  produced.  If  at  once  or  after  half  a  minute  the  milk  becomes 
bluish-grey,  it  indicates  that  it  has  been  heated  to  a  temperature 
of  780  C.  to  8o°  C,  or  1720  F.  to  1760  F.  When  the  color  of  the 
milk  is  unchanged  after  addition  of  the  reagents,  it  may  be 
concluded  that  the  heating  has  exceeded  8o°  C.  The  blue  color 
that  develops  on  standing  has  no  significance.  p 

Storch's  test  has  shown  itself  to  be  the  most  reliable  of  all  the 
methods  proposed  for  distinguishing  heated  from  unheated 
milk.  All  the  so-called  improvements  which  have  been  advo- 
cated by  other  chemists  have  proven  to  be  of  no  benefit,  often 
indeed  the  opposite. 

If  during  the  pasteurization  of  the  milk  the  temperature  falls 
below  8o°  C.  for  a  time,  the  whole  of  the  milk  after  being  mixed 
reacts  to  Storch's  test.  The  sensibility  of  the  test  is  so  great 
that  the  admixture  of  10  per  cent  of  milk  which  has  only  been 
heated  to  78 °  C,  suffices  to  make  the  whole  volume  of  milk  react 
to  the  test. 

Pasteurization  Temperatures. — In  pasteurizing  or  heating 
milk  for  city  trade  or  immediate  consumption,  low  temperatures 
are  used.  This  is  done  for  the  purpose  of  avoiding  a  cooked  or 
heated  taste.  The  method  found  most  satisfactory  for  milk  is 
to  heat  to  1450  F.,  and  hold  at  this  temperature  for  twenty 
minutes.     This  is  known  to  the  trade  as  the  holding  method. 

Where  the  flash  or  instantaneous  method  is  used,  the  milk  or 
cream  is  heated  to  a  temperature  of  1750  to  1900  F.  The  tem- 
peratures most  commonly  used  in  butter-making  in  creameries 
are  180  to  1850  F.  Of  late  years  the  higher  temperatures  have 
been  used  for  butter-making,  even  in  the  holding  method. 

Marker,  in  the  Canadian  Northwest,  recommends  heating  to 
170  or  1 750  F.,  and  holding  for  fifteen  or  twenty  minutes.     This 


PASTEURIZATION  TEMPERATURES  203 

method  of  heating  has  been  recommended  by  him  for  the  pur- 
pose of  destroying  the  enzymes  in  the  cream.  Butter  made  from 
cream  thus  treated  has  shown  unusually  good  keeping  qualities, 
and  he  reports  that  it  does  not  go  fishy  when  placed  in  storage. 
One  of  the  advantages  of  pasteurization  is  that  it  destroys  all  the 
pathogenic  micro-organisms  in  the  cream  if  any  be  present. 
Efficient  pasteurization  destroys  from  99.5  to  99.9  per  cent  of 
the  organisms  present  in  cream.     Pasteurization,  however,  does 


Fig,  66. — The  Simplex  regenerative  pasteurizer  (apart). 

not  put  poor  cream  in  a  condition  where  good  butter  can  be 
made  from  it. 

Pasteurization  and  sterilization  are  not  the  same.  The 
latter  means  that  milk  or  cream,  or  any  other  liquid  substance, 
has  been  heated  so  often  or  to  a  high  enough  temperature  to 
entirely  destroy  every  living  micro-organism  present.  In  order 
to  get  a  substance  thoroughly  sterilized  without  heating  under 
pressure,  it  is  essential  that  it  be  heated  about  thirty  minutes 
on  each  of  three  or  more  consecutive  days. 


204  PASTEURIZATION 

Good  Milk  and  Cream  Important. — The  quality  of  butter 
made  from  pasteurized  cream  will  depend  to  a  very  large  extent 
upon  the  condition  of  the  milk  or  cream  used.  If  milk  or  cream 
is  sweet  and  free  from  obnoxious  flavors  at  the  time  of  pas- 
teurization, the  quality  of  the  butter  made  from  it  will  be  good, 
provided  that  the  butter  is  not  injured  in  the  process  of  manu- 
facturing. The  quality  of  the  cream  used  has  a  bearing  not  only 
upon  the  quality  of  the  butter  made  from  pasteurized  cream  but 
upon  that  made  from  unpasteurized  cream  as  well. 

The  impression  prevails  to  some  extent  that  butter  made 
from  raw  cream  will  not  possess  keeping  qualities  and  that  if 
placed  in  cold  storage  it  will  develop  a  fishy  flavor.  Investiga- 
tions pursued  by  one  of  the  authors  do  not  bear  this  out.  In 
1907  he  conducted  a  series  of  experiments  at  Strawberry  Point 
Creamery,  Strawberry  Point,  Iowa,  during  the  month  of  July. 
This  experiment  was  conducted  under  regular  creamery  con- 
ditions, and  was  carried  on  for  a  period  of  two  weeks.  Apparatus 
was  moved  from  the  Iowa  Experiment  Station  for  making  com- 
plete analyses  of  the  butter  and  records  of  everything  pertaining 
to  this  work  were  kept.  The  Strawberry  Point  Creamery  at  this 
time  was  receiving  about  50,000  pounds  of  milk  daily.  The  milk 
was  received  from  the  patrons  in  cylinder-shaped  20-gallon  cans. 
It  was  inspected  at  the  wagons,  and  any  milk  found  slightly  sour 
or  tainted  was  rejected.  Power  separators  were  used  for  sep- 
arating the  cream  from  the  milk,  and  the  cream  separated  con- 
tained a  high  per  cent  of  fat,  the  fat-content,  after  starters  had 
been  added,  varying  from  37  to  39  per  cent.  The  cream  used  was 
in  as  perfect  a  condition  as  cream  delivered  for  butter-making 
purposes  can  possibly  be.  Pure  culture  starters  were  used  for 
souring  or  ripening  it.  About  half  the  butter  was  made  from 
unpasteurized  cream,  and  the  other  half  from  pasteurized  cream. 
In  every  case,  two  different  churnings  of  butter  were  made 
from  the  same  vat  of  cream,  or  the  cream  was  divided  so  that  two 
separate  churnings  were  made.  The  full  object  of  the  experi- 
ment will  be  dealt  with  in  another  chapter.  Two  60-pound  tubs 
of  butter  were  packed  from  each  churning  and  shipped  to  Gude 
Bros.,  New  York  City.     Each  one  of  these  tubs  bore  a  special 


GOOD  MILK  AND   CREAM  IMPORTANT  205 

number.  When  the  shipment  of  butter  arrived  in  New  York, 
half  was  to  be  sold  in  the  open  market  and  the  other  half  placed 
in  cold  storage.  Three  56-pound  cubical  boxes  were  also  packed 
from  each  churning;  one  of  these  boxes  was  shipped  to  London, 
England,  one  to  Liverpool  and  one  to  Manchester,  for  the  pur- 
pose of  having  the  best  English  experts  score  and  criticize  the 
butter.  The  butter  sent  to  New  York  was  scored  before  going 
into  cold  storage,  and  it  was  rescored  when  it  came  out  of  storage 
by  Mr.  P.  H.  Keiffer,  who  is  generally  recognized  as  an  excep- 
tionally good  judge  of  butter.  One  of  the  authors  was  present 
in  New  York  when  this  butter  came  out  of  storage.  Strange  to 
say,  both  the  pasteurized  and  unpasteurized  butter,  after  being 
in  storage  between  six  and  seven  months,  came  out  of  storage 
scoring  as  high  as  when  they  entered  storage.  Mr.  Keiffer 
remarked  that  it  was  the  finest  lot  of  butter  he  had  ever  seen 
come  out  of  storage  at  that  time.  No  difference  was  found  in 
the  English  market  between  the  scores  of  the  pasteurized  and  the 
unpasteurized  product.  One  of  the  English  judges  scored  some 
of  this  butter  100,  or  perfect.  Hence,  its  excellent  quality, 
whether  pasteurized  or  unpasteurized,  was  due  to  the  quality  of 
the  raw  material  used. 

Cream  of  the  character  mentioned  above  is  not  available  in  the 
average  creamery.  Many  investigations  have  demonstrated 
that  pasteurization  does  produce  butter  of  excellent  keeping 
quality.  In  addition  to  this,  it  entirely  eliminates  the  danger  of 
transmitting  disease  to  human  beings  or  to  animals.  Veteri- 
narians and  scientists  seem  to  be  divided  in  opinion  as  to  whether 
bovine  tubercle  bacilli  can  be  transmitted  to  human  beings, 
but  the  fact  that  tubercle  bacilli  have  been  found  in  a  vigorous 
condition  in  butter  has  a  tendency  to  create  a  fear  in  the  minds  of 
some  people  that  such  a  danger  exists.  For  this  reason  alone, 
if  for  no  other,  cream  should  be  universally  pasteurized  for  butter- 
making,  especially  in  creameries  where  facilities  are  available 
for  doing  work  of  this  kind.  Pasteurization  gives  the  man- 
ufacturer better  control  of  the  cream  so  that  a  more  uniform 
quality  of  butter  can  be  manufactured.  The  wide  adoption 
of  pasteurization  in  this  and  other  countries,  and  the  fact  that 


206 


PASTEURIZATION 


almost  every  city  of  any  size  requires  it  would  seem  to  indicate 
that  it  should  be  made  compulsory.  Since  the  hand  cream  sep- 
arator has  been  generally  adopted  on  the  farm,  pasteurization 
seems  more  necessary  than  before,  as  the  washing  and  cleansing 
of  all  dairy  utensils,  including  the  separator,  is  left  to  the  farmers, 
and  it  is  only  reasonable  to  suppose  that  some  of  them  are  care- 
less. Hence,  we  can  see  the  necessity  for  pasteurization  from  a 
hygienic  standpoint  if  from  no  other. 


wm 


Fig.  67. — The  Simplex  reg»?nerative 
pasteurizer  (assembled). 


Fig.  68. — The  Jensen  pasteurizer. 


Sanitation  Must  Accompany  Pasteurization. — The  chemical 
and  bacteriological  laboratory  of  the  American  Association  of 
Creamery  Butter  Manufacturers  analyzes,  chemically  and  bac- 
teriologically,  samples  of  butter  sent  in  by  members.  Thousands 
of  analyses  are  made  during  the  year.  It  is  found  that  the  butter 
that  contains  the  lowest  counts  of  yeasts  and  molds  is  invariably 
produced  in  the  best  creameries.     Certain  species  of  bacteria, 


SANITATION  MUST  ACCOMPANYPASTEURIZATION         207 

yeasts  and  molds  are  present  in  almost  all  hand  separator  cream 
and  cause  the  deterioration  of  butter  in  storage;  the  elimination 
of  these  micro-organisms  retards  such  deterioration.  Milk  or 
cream  that  is  efficiently  pasteurized  will  contain  neither  yeasts 
nor  molds.  In  laboratory  work  conducted  by  the  Association, 
butter  in  which  the  combined  count  falls  below  ten  yeasts  and 
molds  in  i  c.c.  of  butter  is  considered  good;  in  some  of  the  best 
creameries  the  combined  count  drops  to  five  or  below.  There 
are  other  things  that  affect  the  count  of  yeasts  and  molds  found 
in  butter.  Pasteurization  of  cream  may  be  perfect,  and  yet  the 
cream  may  pass  through  unsanitary  pipes  and  again  be  inocu- 
lated with  yeasts  or  molds.  Vats,  faucets  and  churns  are 
sources  of  contamination.  Of  the  creameries  sending  butter  to 
the  Association  laboratory,  those  whose  butter  shows  the  lowest 
count  of  yeasts  and  molds  are  creameries  that  are  noted  for 
observing  extra  precaution  concerning  sanitary  methods  in  con- 
nection with  all  utensils  that  come  in  contact  with  cream.  They 
use  recording  thermometers  and  automatic  valves  for  regulating 
temperatures  in  pasteurization.  The  first  cream  passing  through 
the  pasteurizer  is  returned  and  reheated.  Butter  made  in  the 
creameries  above-mentioned  sells  constantly  at  a  premium. 
The  quality  of  the  cream  received  by  them  is  no  better  than  that 
received  by  other  creameries  operating  in  the  same  territory, 
which  make  very  inferior  butter. 

Pasteurization  expels  from  the  cream  vapors  and  gases, 
especially  carbon  dioxide  gas;  it  removes  volatile  substances  and 
flavors  absorbed  by  the  cream  or  milk.  The  heating  causes  the 
clusters  of  fat-globules  to  break  up.  Due  to  uniformity  of 
quality  and  pasteurization,  Denmark  has  been  able  to  secure 
almost  absolute  control  of  the  English  market.  Danish  butter 
commonly  sells  at  a  premium  over  any  other  butter  finding  its 
way  to  that  market,  or  at  least  it  did  prior  to  the  war. 

One  of  the  authors  in  discussing  this  subject  with  an  English 
merchant,  who  handled  a  great  deal  of  butter,  asked  for  an 
explanation  of  the  preference  given  to  Danish  butter.  He 
answered  that  they  occasionally  got  better  butter  from  some 
other  countries  but  that  it  did  not  run  uniform  in  quality.     He 


208  PASTEURIZATION 

said  that  the  Danish  butter  was  mild  in  flavor  and  uniform  in 
quality;  in  other  words,  it  suited  the  trade  and  that  was  all  that 
was  wanted. 

Efficient  pasteurization  not  only  enables  the  manufacturer 
to  make  a  more  uniform  grade  of  butter,  but  it  makes  the  butter- 
milk safe  to  feed  to  live  stock,  thus  preventing  the  spread  of 
infectious  diseases.  It  is  said  by  some  that  if  pasteurization  were 
adopted  more  skill  would  be  required  on  the  part  of  the  butter- 
maker.  With  valves  for  controlling  the  steam  pressure  and  the 
use  of  recording  thermometers,  uniform  pasteurization  to  any 
desired  temperature  can  be  brought  about  by  a  maker  of  ordinary 
skill,  if  he  applies  judgment  to  the  details  of  his  creamery  opera- 
tion. « 

Methods  of  Pasteurization. — At  the  present  time  there  are 
three  methods  of  pasteurization  employed  for  butter-making. 
The  one  most  generally  used  is  the  flash  or  instantaneous  heating 
method.  Under  this  method  the  cream  is  heated  to  a  high 
temperature,  1800  or  1850  F.,  and  quickly  cooled,  by  passing 
over  a  cooler,  to  ripening  temperature  or  to  churning  tempera- 
ture, as  the  case  may  be.  In  the  vat,  or  holding,  method  cream 
is  usually  heated  to  a  temperature  of  1500  to  1600  F.,  held  at 
this  temperature  for  twenty  to  twenty-five  minutes,  and  cooled 
to  ripening  or  churning  temperature.  Some  use  the  combined 
flash  and  holding  method. 

Some  of  the  best  creameries  that  use  the  flash  method,  or  high 
temperatures,  follow  what  is  known  as  the  double  system  of 
pasteurizing.  Two  pasteurizers  are  attached  to  each  other; 
the  cream  passes  to  the  first  pasteurizer  from  the  forewarmer, 
where  it  is  heated  to  a  temperature  of  about  13  5  °  or  1400  F.  It 
passes  from  the  first  to  the  second  pasteurizer  where  it  is  heated 
to  185 °  F.,  or  any  temperature  desired.  The  live  steam  is  con- 
nected with  the  second  pasteurizer,  and  the  exhaust  steam  from 
the  second  pasteurizer  furnishes  heat  for  heating  the  cream  in 
the  first  pasteurizer  to  1400  F.,  or  thereabout.  The  heating  of 
the  cream  in  the  first  pasteurizer  increases  the  fluidity  of  the 
cream.  Hence,  when  it  enters  the  second  pasteurizer,  the  heat 
comes  in  contact  with  all  particles  of  the  cream,  and  the  efficiency 


METHODS  OF  PASTEURIZATION  209 

of  pasteurization  is  thereby  increased.  From  general  observa- 
tion of  work  in  many  creameries  belonging  to  the  American 
Association  of  Creamery  Butter  Manufacturers,  the  authors 
feel  safe  in  recommending  this  system. 

One  of  the  authors  first  saw  this  system  in  general  use  at  the 
Experiment  Station  at  Kiel,  Germany,  something  over  twenty 
years  ago.  Dr.  Weigman  was  heating  to  1900  F.  at  that  time, 
and  claimed  very  satisfactory  results. 

The  relative  merits  of  the  two  systems — the  vat  system  where 
the  heating  is  done  through  a  coil,  or  the  use  of  a  machine  con- 
structed exclusively  for  pasteurizing  milk  and  cream — depend 
largely  upon  local  conditions.  If  the  first  cost  only  is  taken 
into  consideration,  cream  can  be  pasteurized  more  cheaply  under 
the  vat  system,  as  the  heating  and  the  cooling  are  done  in  the 
same  vat.  In  a  small  creamery  where  space  has  to  be  taken  into 
consideration,  the  vat  system  is  to  be  recommended.  Not  only 
does  it  require  less  space  but  it  involves  less  labor.  The  objections 
to  the  vat  system  are,  first,  that  the  vat  is  not  constructed  for  a 
pasteurizer,  and,  second,  that  the  wear  and  tear  (heating  and 
cooling,  and  expansion  and  contraction)  will  affect  the  life  of 
the  vat.  These  are  items  that  must  be  taken  into  consideration 
when  figuring  the  cost  over  a  period  of  years.  In  a  factory  where 
a  large  volume  of  business  is  transacted,  the  regular  pasteurizer 
would  be  preferable.  It  is  much  stronger  than  the  vat  and  is 
constructed  exclusively  for  the  purpose  of  pasteurizing  cream. 
In  addition  to  this  a  greater  amount  of  cream  can  be  cared  for  in  a 
shorter  space  of  time.  The  cooling  is  done  much  more  quickly 
where  a  regular  cooler  is  used.  Another  advantage  is  that  the 
heating  and  cooling  are  not  done  in  the  same  vat,  thus  avoiding 
the  expansion  and  contraction  of  the  metals. 

Some  use  the  method  of  heating  in  the  flash  pasteurizer  and 
cooling  in  a  vat.  This  does  away  with  the  necessity  for  a  cooler, 
but,  as  stated  above,  the  cooling  is  not  done  as  rapidly  as  it  would 
be  if  a  regular  cooler  were  used.  This  system  works  well  where 
the  holding  system  is  practiced  and  lower  temperatures  are  used 
for  pasteurizing.  Cream  can  be  run  into  the  ripening  vat  from 
the  flash  pasteurizer,  held  any  desired  time  and  cooled  with  a  coil. 


210  PASTEURIZATION 

Under  the  regenerative  principle  the  cold  cream  is  heated 
by  the  hot  cream  passing  from  the  pasteurizer.  In  the  outflow, 
hot  cream  is  cooled  by  the  cold  cream  flowing  into  the  pas- 
teurizer. The  hot  and  cold  cream  then  equalize  their  respective 
temperatures  by  passing  in  different  directions.  It  is  claimed  by 
manufacturers  of  these  pasteurizers  that  they  effect  a  saving  of 
25  per  cent,  or  more. 

Most  pasteurizers  at  the  present  time  are  constructed  of 
heavy  copper  coated  with  tin.  The  heating  surface  of  some  of 
these  pasteurizers  is  lined  with  German  silver.  From  the  stand- 
point of  heat  conductivity  there  is  little  choice  between  these  two 
metals.  It  is  a  well-known  fact  that  some  metals  will  conduct 
heat  better  than  others;  the  relative  heat  conductivities  of 
copper  and  tin  are  .918  and  .145  respectively.  This  means  that 
copper  will  conduct  heat  nearly  seven  times  as  fast  as  tin  of  the 
same  thickness,  and  therefore  that  copper  might  be  seven  times 
as  thick  as  tin  and  still  transmit  as  much  heat  as  the  tin.  From 
this  it  can  be  seen  that  a  heating  wall  made  from  copper  can  be 
increased  slightly  in  thickness,  and  thus  aid  in  stability,  without 
affecting  the  degree  of  heat  conductivity  of  the  wall  very  much. 
The  heating  surface  must  be  strong  enough  to  withstand  a 
slight  steam  pressure,  otherwise  the  heating  wall  is  likely  to 
collapse  or  cave  in,  in  case  of  slight  variation  in  the  steam  pressure. 
It  used  to  be  a  rather  common  occurrence  for  the  heating  walls  of 
the  pasteurizer  to  cave  in  or  collapse  in  case  of  a  slight  variation 
in  the  steam  pressure.     This  does  not  happen  so  often  now. 

The  condition  of  the  cream  has  some  bearing  on  the  heating 
surface.  Sour  and  coagulated  cream  burns  and  adheres  to  a 
greater  extent  than  does  sweet  cream.  This  is  evidently  due  to 
the  lesser  fluidity  of  the  sour  cream.  Where  two  pasteurizers 
are  used,  this  tendency  is  overcome  to  a  very  large  extent. 

Efficiency  of  Pasteurizers. — Experiments  conducted  by  Dr. 
Storch  of  the  Royal  Experiment  Station,  Copenhagen,  Denmark, 
show  that  condensed  steam  offers  great  resistance  to  the  trans- 
mission of  heat.  The  comparative  heat  conductivities  of  water 
and  copper  are  .0016  and  .9  respectively,  as  found  by  Dr.  Storch. 
It  will  thus  be  seen  that  copper  is  600  times  as  good  a  conductor 


EFFICIENCY  OF  PASTEURIZERS 


211 


of  heat  as  water  is.  This  would  mean  that  a  quiet  layer  of  water 
3  mm.  in  thickness  would  offer  the  same  resistance  to  heat  as  a 
layer  of  copper  2  meters  in  thickness.  Consequently  a  very 
thin  layer  of  water  or  condensed  steam  on  the  sides  of  the  heating 
wall  would  greatly  interfere  with  the  economic  efficiency  of  a 
pasteurizer. 

In  order  to  overcome  this  difficulty  drip-rings  were  circled 


Fig.  69. — Jensen  sanitary  pasteurizer-regeneratcr  and  cooler  (Jensen 
Creamery  Machinery  Co.). 


round  the  drum  of  the  pasteurizer,  at  intervals,  on  the  steam  side 
of  the  heating  surface.  The  first  rings  put  around  the  pas- 
teurizer were  narrow,  smooth  bands.  These  did  not  give  entire 
satisfaction,  as  the  condensed  water  from  the  top  rings  would 
drip  on  the  edge  of  the  lower  ones,  and  cause  the  water  to  spatter 
over  the  side  of  the  heating  wall.  Another  kind  of  ring  was  then 
invented   which  was  thin,  narrow,  and  provided  with  teeth  like 


212 


PASTEURIZATION 


those  of  a  saw.  The  rings  were  fastened  to  the  heating-wall  at 
proper  intervals  at  an  angle  of  45 °.  The  rings  were  so  arranged 
that  the  drops  of  condensed  water  escaping  from  the  end  of  each 
saw-tooth  would  fall  in  the  hollow  between  the  teeth  in  the  lower 
rings  and  thus  prevent  any  spattering  of  the  water  against  the 
heating  wall.     These   contrivances  greatly  increased   the  em- 


Eig.  70. — Elyria  pasteurizer  (Elyria  Enameled  Products  Co.). 

ciency — as  much  as  48  per  cent — and  the  capacity  of  the  pas- 
teurizer experimented  with. 

Cost  of  Pasteurization. — Dr.  Storch  in  his  forty-third  report 
at  the  Royal  Experiment  Station  at  Copenhagen,  Denmark, 
reported  that  it  required  80  pounds  of  steam  to  heat  1000  Danish 
pounds  of  milk  from  400  C.  to  850  C.     This  would  be  equivalent 


COST  OF  PASTEURIZATION 


213 


under  American  conditions  to  about  90  pounds  of  steam  to  pas- 
teurize 1000  pounds  of  milk  from  900  F.  to  1850  F. 

According  to  good  authorities,  it  takes  about  1  pound  oHump 
coal  to  produce  6  pounds  of  steam,  although  much  depends  upon 
the  fireman  and  the  construction  of  the  boiler.  Based  upon 
this  estimate,  it  would  take  15  pounds  of  coal  to  produce  90 
pounds  of  steam.  If  the  coal  cost  $4.00  per  ton,  the  cost  of 
the  15  pounds  would  be  3  cents.  If  the  milk  tested  3.6  per  cent 
fat,  the  calculation  upon  one-sixth  overrun  of  1000  pounds  of 
milk  would  produce  42  pounds  of  butter.  The  cost  of  pasteuriz- 
ing the  milk  producing  42  pounds  of  butter  would  then  be  3 
cents,  and  the  cost  of  pasteurization  per  pound  of  butter  would  be 
.07  of  a  cent. 

The  figures  submitted  by  Storch,  however,  were  obtained  a 
number  of  years  ago,  and  cannot  be  applied  to  conditions  in  this 
country  at  the  present  time. 

Mortensen,  who  has  given  a  good  deal  of  thought  to  the  cost 
under  the  continuous  and  vat  methods,  estimates  as  follows: 


Continuous 

Method, 

Cents 

Vat  Method, 
Cents 

Cost  of  steam 

.019 
.009 
.181 

Cost  of  water 

.021 

Cost  of  labor  and  equipment 

•054 

Total 

.209 

.091 

The  cost  in  different  factories  would  vary  with  the  cost  of  fuel. 
With  the  high  railroad  rates  prevailing  at  the  present  time 
and  the  high  price  of  labor,  we  can  estimate  the  cost  at  about 
one-fifth  of  a  cent  per  pound. 

In  addition  to  this,  the  loss  of  fat  in  buttermilk  seems  to  be  a 
trifle  more  in  pasteurized  than  in  unpasteurized  cream.  This 
may  be  due  to  the  precipitation  of  the  casein  by  heat.  Pas- 
teurization is  necessary  from  a  hygienic  standpoint.  It  gives  a 
guarantee  to  the  consuming  public  that  all  pathogenic  bacteria 


214  PASTEURIZATION 

are  destroyed.  It  takes  away  from  the  enemies  of  butter  the 
opportunity  of  proclaiming  that  disease  may  be  transmitted  to 
the  human  family  through  this  article  of  diet.  There  is  less 
danger  of  transmitting  disease  through  butter  than  through  any 
other  dairy  product. 

The  senior  author  has  been  for  more  than  thirty  years  engaged 
in  the  butter  business  in  various  capacities,  from  manufacturer  to 
conductor  of  investigational  work,  and  has  never  known  of  a 
case  where  any  disease  was  transmitted  through  butter,  from 
either  pasteurized  or  raw  cream.  It  has  been  demonstrated  in 
all  parts  of  the  world  that  raw  or  unpasteurized  milk  will  transmit 
bacillus  typhosus.  The  first  epidemic  of  typhoid  fever  which 
was  traced  to  infected  milk  was  one  occurring  at  Penrith  in 
1858  (Taylor).  Since  that  time  cases  have  become  so  numerous 
that  almost  all  municipalities  insist  upon  efficient  pasteurization 
of  milk. 

In  addition  to  the  effect  that  pasteurization  may  have  on 
butter,  pasteurization  of  the  skim-milk  and  cream  puts  both  the 
skim-milk  and  buttermilk  in  a  condition  where  there  is  no  danger 
of  transmitting  disease  to  animals. 

Disadvantages  of  Pasteurization. — The  disadvantages  of  pas- 
teurization are,  first,  the  cost  of  installing  equipment,  and,  second, 
the  additional  cost  of  operation.  Due  to  the  increased  cost  of 
labor  in  recent  years,  it  is  difficult  accurately  to  estimate  the  cost. 

Advantages  of  Pasteurization. — The  advantages  of  pas- 
teurization far  outweigh  the  disadvantages,  and  may  be  sum- 
marized as  follows: 

(1)  It  destroys  pathogenic  bacteria  if  there  be  any  present 
in  milk  and  cream,  and  renders  them  and  their  products  and  by- 
products perfectly  safe  as  foods. 

(2)  It  destroys  practically  all  germ  life  and  enables  the  butter- 
maker  to  produce  a  more  uniform  quality  of  butter. 

(3)  It  is  one  of  the  large  factors  which  improve  the  keeping 
quality  of  butter. 

(4)  It  eliminates  some  of  the  taints  in  cream. 


CHAPTER  XVI 
CREAM-RIPENING  AND  STARTERS 

CREAM-RIPENING 

Definition. — By  cream-ripening  we  mean  the  treatment 
cream  receives  from  the  time  it  is  put  into  the  ripening- vat  until 
it  is  put  into  the  churn;  and  also  the  chemical,  biological,  and 
physical  changes  it  undergoes  during  this  time. 

In  the  whole-milk  creameries  and  in  a  few  of  the  creameries 
receiving  only  cream,  the  cream  goes  into  the  ripening  vat  in  the 
morning  and  no  more  is  added  during  the  day.  In  most  cream- 
eries, however,  cream  is  taken  in  throughout  the  day.  This 
system  does  not  permit  of  such  perfect  ripening  of  the  cream; 
besides,  it  necessitates  opening  and  closing  the  vat  at  intervals. 
Under  this  latter  system  it  is  important  that  the  cream  vat  have  a 
fly  screen  over  it,  and  that  one  end  of  it  be  covered  with  a  cream 
strainer  through  which  all  cream  is  strained  before  it  enters  the 
vat. 

Objects  of  Ripening.  To  Produce  Flavor  and  Aroma. — 
The  chief  object  of  cream-ripening  is  to  secure  the  desirable 
and  delicate  flavor  and  aroma  which  are  so  characteristic  of  good 
butter.  The  necessary  flavoring  substances,  so  far  as  known, 
can  only  be  produced  by  a  process  of  fermentation.  Good  butter 
possesses  two  characteristic  flavors.  One  is  known  as  palate 
flavor,  or  the  distinctive  butter  flavor.  The  other  is  what  is 
described  by  butter  judges  as  a  nose  flavor  or  aroma,  sometimes 
described  as  "  bouquet  "  flavor.  While  the  flavor  and  aroma 
characteristic  of  good,  properly  ripened  cream  and  the  butter 
made  from  it  are  produced  by  fermentation,  the  chemical  changes 
that  produce  them  are  not  well  understood.  It  is  claimed  by 
some  that  the  palate  flavor  is  derived  from  the  volatile  fatty 

215 


216 


CREAM-RIPENING  AND   STARTERS 


acids,  and  the  aroma  from  a  fermentation  of  the  milk-sugar. 
Good  cream  must  possess  a  clean,  pleasant,  acid  taste.  For  this 
reason,  it  is  essential  to  have  the  acid-producing  germs  predom- 
inate during  cream-ripening. 

Butter  has  been  made  from  sour  cream  from  time  immemorial. 
Housewives  discovered  a  great  many  years  ago  that  butter  made 
from  ripened  cream  had  a  more  pronounced  flavor  and  aroma 
than  butter  made  from  unripened  cream.  They  also  found 
that  cream  properly  ripened  would  churn  more  easily  and  give  a 


Fig.  71  —Progress  vat  pasteurizer  and  cream-ripener. 
Dairymens  Mfg.  Co.) 


(Davis-Watkins 


more  exhaustive  churning;  hence,  the  practice  of  souring  cream 
has  been  handed  down  to  the  creameries  from  the  home  dairies. 
Some  women  became  noted  for  making  butter  of  an  exceptionally 
fine  quality,  because,  in  addition  to  observing  cleanliness  as  the 
first  requisite  in  making  good  butter,  they  selected  nice,  clean- 
flavored  milk  and  let  it  sour  naturally;  this  was  added  to  the 
cream  for  the  purpose  of  hastening  the  souring  or  ripening. 
Some  of  these  dairies  produced  butter  which  was  not  only  of  good 
quality  but  also  possessed  good  keeping  qualities. 

In  the  early  days  of  butter-making  it  was  customary  for  some 
to  pack  their  butter  in  glazed  crocks  during  the  latter  part  of  May 


CREAM-RIPENING  217 

or  the  first  part  of  June,  cover  it  with  salt  and  hold  it  until  the 
winter  months,  keeping  it  in  the  cellar  or  some  other  cool  place 
until  it  was  used  up.  As  dairying  advanced  and  butter-began 
to  be  made  on  a  large  scale  in  creameries,  in  various  countries, 
the  bacteriologist  resorted  to  the  method  of  isolating  certain 
species  of  bacteria  for  the  purpose  of  ripening  cream  and  pro- 
ducing the  desired  flavor. 

It  has  not  yet  been  proved  that  any  particular  species  of 
bacteria  is  responsible  for  the  production  of  fine  flavor  in  butter. 
It  is  generally  agreed  that  the  flavoring  substances  developed 
during  the  ripening  of  cream  are  decomposition  products  of  bac- 


Fig.  72. — Wizard  vat  pasteurizer  and  cream-rlpener.      (Creamery  Package 

Mfg.  Co.) 

terial  growth,  and  it  has  been  generally  recognized  that  the  types 
producing  the  lactic  acid  are  the  most  desirable  ones  to  have 
present  in  cream.  There  are  a  great  many  bacteria  in  milk  and 
cream  which  produce  acid,  over  one  hundred  species  have  been 
studied  and  described.  It  is  apparent,  however,  that  only  a 
comparatively  few  of  these  produce  the  best  results  in  cream- 
ripening.  Hence,  in  the  preparation  of  a  natural  starter,  great 
care  should  be  exercised  in  selecting  milk  that  will  sour  with  a 
pleasant  acid  taste. 

At  the  Iowa  Experiment  Station,  McKay  and  Eckles  con- 
ducted a  series  of  tests  on  fermentation  by  taking  milk  from 
different  patrons'  herds,  placing  it  in  sterile  glass  bottles  and 
allowing  it  to  sour  naturally.     It  was  found  that  milk  which 


218  CREAM-RIPENING  AND   STARTERS 

began  to  whey  off  at  the  bottom  of  the  jar,  soon  after  coagula- 
tion, due  to  certain  species  of  bacteria  decomposing  the  casein, 
invariably  possessed  an  undesirable  flavor.  Samples  of  milk 
which  would  remain  coagulated  for  some  time  and  whey  off  at 
the  top  possessed  a  pleasant  acid  flavor.  By  selecting  such 
samples  of  milk  for  preparing  natural  starters,  these  investi- 
gators were  able  to  produce  starters  that  gave  excellent  results 
in  cream-ripening. 

Butter  made  at  the  school  that  scored  the  highest  at  one  of 
the  large  national  conventions,  receiving  a  score  of  98,  was  made 
from  cream  that  had  been  ripened  by  a  natural  starter.  T^e 
whole  milk,  received  at  the  creamery  when  two  days  old,  was 
skimmed  so  as  to  contain  a  very  high  per  cent  of  milk-fat.*  The 
object  was  to  concentrate  the  fat  and  get  rid  of  as  much  of  the 
skim-milk  with  its  undesirable  bacteria  as  possible,  and  then 
dilute  the  cream  with  fresh  milk  from  the  herds  whose  milk 
showed  desirable  results  when  souring  naturally.  The  addition 
of  a  starter  ripened  naturally  from  the  above-mentioned  milk, 
ripened  the  cieam  which  produced  the  high-scoring  butter. 

Another  test  was  made  in  a  national  contest  where  dif- 
ferent parties  were  placed  in  charge  of  the  ripening,  taking  the 
entire  milk  as  it  came  in  on  four  different  days,  and  the  same 
method  was  followed  with  correspondingly  favorable  results. 
In  this  contest,  in  which  about  eight  hundred  creameries  com- 
peted, the  butter  made  by  this  method,  on  these  four  different 
days  scored  the  highest,  third,  fourth  and  fifth  in  flavor.  This  is 
a  further  substantiation  of  what  has  been  reported  by  various 
investigators,  Storch,  Conn  and  others,  that  the  flavor  developed 
depends  very  largely  upon  the  species  of  germ  life  that  predom- 
inate. 

Where  cream  has  been  pasteurized  and  inoculated  with  a 
starter  containing  the  right  organisms,  the  effects  of  the  starter 
will  be  more  pronounced  than  if  the  cream  were  manufactured 
raw  or  unpasteurized.  This  is  due  to  the  fact  that  the  promis- 
cuous assortment  of  organisms  in  the  natural  bacterial  flora  is 
largely  destroyed  by  the  heating  process  in  pasteurization.  Bac- 
teriologists do  not  agree  as  to  what  species  of  bacteria  is  respon- 


CREAM-RIPENING  219 

sible  for  the  high  flavor  and  aroma  of  butter.  Conn  claims  that 
the  germs  which  act  upon  the  nitrogenous  matter  of  milk  are 
associated  with  the  lactic-acid-producing  bacteria  in  the-  pro- 
duction of  desirable  butter  flavors.  Weigman  asserts  that 
the  best  results  are  obtained  when  a  variety  of  species  work 
together  in  the  cream.  He  has  isolated  a  single  species  of  germ 
which  produces  alcohol  and  lactic  acid  as  by-products,  and  which 
according  to  experimental  evidence  deduced  by  him,  is  capable 
of  producing  the  delicate  butter  flavors.  Freudenreich  also 
studied  a  species  of  germ  which  produced  alcohol  and  lactic  acid 
as  by-products,  and  which  he  claimed  was  able  to  produce  the 


Fig.  73. — Cherry  vat  pasteurizer  and  cream-ripener.      (J.  G.  Cherry  Co.) 

characteristic  butter  flavors.  Eckles  studied  the  question  of 
flavor  production  during  cream-ripening.  He  came  to  the  con- 
clusion that  the  flavor  and  aroma  substances  developed  during 
cream-ripening  may  be  produced  by  a  variety  of  acid-producing 
bacteria.  He  asserts  that  of  the  species  tried  the  most  common 
milk-souring  organism  {Bacterium  lactarii)  gave  the  most  satis- 
factory results  as  a  culture  for  ripening  cream.  Storch,  who  has 
perhaps  studied  this  question  to  as  great  an  extent  as  any  of  the 
investigators,  maintains  that  the  germs  producing  lactic  acid  are 
essential  to  good  cream-ripening,  and  that  the  flavor  and  aroma 
products  are  the  results  of  the  joint  action  of  a  great  many 
species  of  lactic-acid-producing  germs.  Tiemann  finds  that  an 
addition  of  a  small  amount  of  hydrochloric  acid  to  the  cream  does 


220 


CREAM-RIPENING  AND   STARTERS 


not  produce  the  characteristic  flavor,  and  indicates  that  the 
process  of  fermentation  is  necessary  to  secure  the  proper  flavors. 
The  study,  by  Hammer  and  Bailey  of  the  Iowa  Station,  of  the 
causes  of  flavor  and  aroma  development  in  cream-ripening  is 
briefly  outlined  in  the  section  of  this  chapter  on  "  Starters." 


toofcti 


Fig.  74.— Vertical  universal  ripener  and  pasteurizer.      ^ Jensen  Creamery 
Machinery  Co.) 


This  is  probably  the  fullest  investigation  of  this  subject — in 
America  at  least — that  has  been  conducted  in  recent  years. 

Ripening  Temperature  of  Cream. — In  regular  practice  the 
ripening  temperature  of  cream  usually  ranges  between  6o°  and 
750  F.     The  lactic  acid  organisms  and  those  associated  with  them 


CREAM   RIPENING  221 

in  a  good  starter  have  the  greatest  relative  growth  at  700  F.,  or  a 
little  above.  Generally  speaking,  it  is  advisable  to  adopt  a  little 
lower  ripening  temperature  in  summer  than  in  winter.  For^  one 
thing,  the  cream  has  a  tendency  to  rise  a  little  in  temperature  in 
summer  and  to  fall  a  little  in  winter,  during  the  time  of  ripening; 
and  furthermore,  the  natural  bacterial  flora  present  in  summer  are 
more  favorable  to  cream-ripening  than  those  present  in  winter. 
With  the  necessary  modifications  to  meet  conditions,  65 °  to  700 
will  be  found  a  suitable  range  of  temperature  to  adopt  during  the 
summer  season  and  700  to  74 °  during  the  fall  and  winter  months. 
The  amount  of  starter  used  and  the  length  of  the  ripening  period 
are  factors  that  must  be  considered  in  deciding  upon  the  tem- 
perature to  be  used.  Where  a  fairly  high  ripening  temperature 
is  adopted  a  little  greater  precaution  must  be  taken  to  prevent 
over-ripening  of  the  cream,  particularly  if  a  liberal  amount  ol  a 
good,  active  starter  be  used. 

Amount  of  Starter  to  Add  to  Cream. — The  amount  of  starter 
to  add,  the  ripening  temperature  and  the  length  of  the  ripening 
period  are  related  factors  that  influence  each  other.  Also  the 
richness  of  the  cream  places  a  limit  upon  the  amount  of  starter 
that  can  be  used.  Generally  speaking,  where  the  separating  is 
done  on  the  farm  the  richness  of  a  vat  of  cream  is  not  so  great  as 
where  the  milk  is  delivered  to  and  separated  at  the  creamery, 
and  consequently  it  is  not  practicable  to  use  so  high  a  per  cent 
of  starter  in  the  former  as  in  the  latter  case.  The  quantity  of 
starter  used  will  range  from  ic  to  20  per  cent,  depending  upon  the 
ripening  temperature  adopted,  the  richness  of  the  cream,  the  time 
within  which  the  ripening  is  to  be  done,  and,  to  some  extent,  the 
cost  of  the  milk  or  skim-milk  used  in  making  the  starter. 

Mixing  the  Starter  with  the  Cream.— When  the  starter  is 
added  to  a  vat  of  cream  the  coils  should  be  run  for  a  few 
minutes  in  order  to  mix  the  two  very  thoroughly.  This  is 
necessary  to  insure  uniformity  of  ripening. 

Tests  for  Acidity. — The  acid  in  cream  is  developed  in  the  milk- 
serum,  and  the  per  cent  of  butter-fat  that  cream  contains  merely 
takes  up  space.  Hence,  in  ripening  cream  some  consideration 
should  be  given  to  the  per  cent  of  fat  in  it,  as  the  fat  is  a  neutral 


222 


CREAM-RIPENING  AND   STARTERS 


quantity.  For  instance,  it  is  not  safe  to  develop  as  high  a  per 
cent  of  acid  in  cream  containing  40  per  cent  as  could  be  devel- 
oped in  cream  containing  25  or  30  per  cent  of  fat.  For  this  and 
other  reasons  it  is  advisable  to  use  a  special  test  with  which  to 
measure  the  amount  of  acid  developed  in  the  cream.  There  are 
two  acid  tests  in  general  use  now  in  creameries,  viz.,  "  Mann's 
Test  "  and  the  "  Farrington  Test." 

Mann's  Test. — Mann's  test  consists  of  measuring  the  acid  in 


Fig.  75. — A  creamery  equipped  with  glass  enameled  tanks  and  vats. 


the  cream  by  means  of  an  alkali  of  a  definite  strength.  The  kind 
of  alkali  used  is  usually  a  tenth  normal  solution  of  caustic  potash 
(KOH)  or  caustic  soda  (NaOH).  These  solutions  can  be  made 
up  very  cheaply  or  bought  from  the  supply  houses.  Mann's 
test  is  based  upon  measuring  out  50  c.c.  of  cream  by  means  of  a 
pipette.  While  the  test  is  based  on  50  c.c.  of  cream  a  25  c.c. 
pipette  can  be  used,  and  the  reading  multiplied  by  two,  thus 
avoiding  the  necessity  of  using  so  much  cream.  Even  a  smaller 
pipette  could  be  used,  but  25  c.c.  is  preferable  to  a  smaller  quan- 
tity, which  would  increase  the  danger  of  error.     A  few  drops  of  an 


CREAM-RIPENING 


223 


indicator  (phenolphthalein)  are  added.  This  indicator  gives  a 
red  color  in  an  alkaline  solution,  and  no  color  in  an  acid  solution. 
The  tenth  normal  alkali  solution  is  poured  into  a  burette,  _and 
allowed  to  run  into  the  50  c.c.  or  25  c.c.  of  cream  (which  is  kept 
stirred  thoroughly)  until  it  begins  to 
turn  pink  in  color.  At  this  point  it  is 
neutral.  The  number  of  cubic  centi- 
meters of  alkali  required  to  neutralize 
the  acid  in  50  c.c.  of  cream  indicates  the 
number  of  degrees  of  acid.  For  in- 
stance, if  it  should  require  32  c.c.  of  a 
tenth  normal  alkali  to  neutralize  the  acid 
in  50  c.c.  of  cream,  the  acidity  of  the 
cream  would  be  320.  (1  c.c.  of  N/10 
alkali  =  1  °  Mann's  Test.) 

Mann's  test  reading  can  be  con- 
verted so  as  to  express  the  results  in 
percentage  similar  to  the  Farrington 
test.  As  1  c.c.  of  the  tenth  normal 
alkali  neutralizes  .009  gram  of  pure  lactic 
acid,  32  c.c,  as  in  the  above  case,  would 
neutralize  32  times  .009.  This  would 
give  the  amount  of  acid,  calculated  in 
terms  of  lactic  acid,  present  in  the  50  c.c. 

of  cream.     This  product  divided  by  the  50,  and  multiplied  by 
100,  would  give  the  percentage  of  the  acid  present. 

Farrington  Test. — The  same  principle  is  involved  in  the  Far- 
rington test.  The  alkali  is  put  up  in  small  tablets,  already 
containing  the  indicator.  These  tablets  contain  a  definite 
amount  of  alkali,  and  are  represented  as  retaining  their  strength. 
They  lose  it,  however,  if  they  are  exposed  to  the  atmosphere.  The 
amount  of  alkali  in  each  tablet  is  such  that  when  five  of  them  are 
put  into  a  graduated  cylinder,  the  cylinder  rilled  up  with  dis- 
tilled water  to  the  97  c.c.  mark,  and  the  tablets  thoroughly 
dissolved  in  it,  a  solution  is  obtained,  each  cubic  centimeter  of 
which  represents  .01  of  1  per  cent  of  acid,  provided  17.6  c.c.  of 
cream  are  taken.     The  tablets  can  be    made  up    of  different 


Fig.  76.  —  Apparatus  for 
Mann's  acid  test.  Instead 
of  the  burette  the  alkali 
can  be  kept  in  a  large 
bottle,  as  shown  in  Figs. 
77  and  78. 


224 


CREAM-RIPENING  AND   STARTERS 


strengths  for  the  use  of  different-sized  pipettes,  but  as  the  17.6 
c.c.  pipette  is  the  one  which  is  used  in  the  ordinary  Babcock  test, 
directions  are  given  for  the  use  of  this  pipette  only.  For  a 
more  detailed  description  of  the  acid  tests  see  "  Testing  Milk  and 
its  Products,"  by  Farrington  and  Woll. 

Degree  of  Acidity  that  Cream  Should  be  Ripened  to. — As  to 


Fig.  77. — Arrangement  for  keep- 
ing alkali  for  the  Mann's  test. 


Fig.  78. 


the  per  cent  of  acid  that  should  be  developed  in  cream,  this  will 
depend  upon  such  factors  as  the  richness  of  the  cream,  the  market 
demands  as  to  fullness  of  flavor  in  the  butter,  whether  the  cream 
is  sweet  cream  or  cream  that  has  previously  soured  and  been 
neutralized,  and  the  length  of  time  the  butter  is  likely  to  be  held 
in  storage. 


STARTERS 


225 


As  has  already  been  pointed  out,  rich  cream  should  not  show- 
as  high  a  per  cent  of  acid  when  ripened  as  cream  with  a  lower 
fat-content.  If  it  should  do  so  it  is  really  a  riper  cream,  tha^isy 
the  skim-milk  portion  of  it  has  been  ripened  to  a  higher  degree 
of  acidity. 

Where  cream  has  soured  and  been  neutralized  before  pas- 
teurization, it  is  advisable  not  to  ripen  to  as  high  a  degree  of 
acidity  as  might  be  developed  were  the  cream  sweet  to  begin 


Fig.  79. — Apparatus  for  the  Farrington  acid  test. 

with.     Especially  does  this  apply  when  butter  is  likely  to  be  held 
any  length  of  time. 

Unless  market  conditions  demand  it — and  it  is  only  in  very 
exceptional  cases  that  they  do — it  is  not  advisable  to  ripen 
average  cream,  or  cream  with  a  fat-content  of  about  30  per  cent 
to  an  acidity  of  over  .50  to  .55  per  cent.  It  is  safer  to  err  a  trifle 
on  the  side  of  underripening  rather  than  to  overripen  cream. 


STARTERS 

Definition. — By  the  term  starter,  in  cream-ripening,  we 
understand  a  medium  containing  a  preponderance  of  desirable 
germs  present  in  a  vigorous  condition. 


226  CREAM-RIPENING  AND  STARTERS 

History. — The  use  of  starters  in  the  dairy  industry  dates 
back  a  great  many  years.  The  fact  that  starters  helped  in  the 
manufacture  of  dairy  products  was  recognized  years  ago  by 
practical  men  even  before  scientists  recommended  the  use  of 
pure  cultures.  In  European  dairy  countries  the  use  of  the 
buttermilk  borrowed  from  a  neighboring  factory  to  add  to  the 
cream  in  order  to  overcome  abnormal  conditions,  was  a  common 
occurrence.  In  Holland,  sour  whey  borrowed  from  some  other 
factory  was  used  to  overcome  gassy  fermentation  in  cheese- 
making.  While  the  reasons  for  this  were  not  well  understood, 
the  underlying  principle  involved  was  that  of  overcoming  the 
undesirable  fermentation  by  adding  ferments  of  an  antagonistic 
kind. 

The  introduction  of  commercial  starters  for  cream-ripening 
dates  back  to  1890,  when  Professor  S torch  recommended  their 
use  in  creameries  in  Denmark.  After  commercial  starters  had 
been  used  long  enough  in  that  country  to  demonstrate  their 
worth,  they  were  introduced  into  this  as  well  as  practically  all 
the  European  countries,  and  are  now  used  quite  extensively. 

Classification  of  Starters. — Generally  speaking,  the  different 
kinds  of  starters  are  included  under  the  names  (1)  Natural, 
and  (2)  Commercial.  The  latter  are  prepared  from  a  culture 
of  bacteria  obtained  from  the  laboratory.  The  former,  or  nat- 
ural, include  a  great  many  kinds  of  dairy  products  which 
are  supposed  to  contain  a  preponderance  of  those  germs  which 
are  involved  in  the  production  of  desirable  flavors  in  butter. 
Buttermilk,  sour  cream,  whey,  and  soUr  whole  or  skim-milk, 
are  classed  under  this  heading.  While  all  these  may  be  termed 
natural  starters,  and  at  certain  times  the  use  of  any  one  of  them 
may  produce  better  results  than  if  no  starter  at  all  were  used, 
it  is  not  safe  to  rely  upon  them  to  TDring  about  better  results 
than  could  be  obtained  without  the  use  of  starters,  because  these 
products  are  likely  to  be  contaminated  in  a  large  degree  with 
undesirable  germs. 

Preparation  of  Natural  Starters. — The  best  natural  starter 
is  usually  obtained  by  selecting  a  number  of  different  samples 
of  the  best  milk  coming  into  the  creamery  and  putting  them 


STARTERS  227 

into  cleaned  sterile  glass  jars.  The  samples  are  allowed  to  stand 
until  sour  at  about  700  F.  The  sample  which  coagulates  into  a 
smooth  uniform  curd,  and  has  a  pleasant  acid  taste  and  smell-is 
selected  and  used  as  a  mother-starter.  When  a  large  quantity 
of  selected  pasteurized  milk  or  skim-milk  is  inoculated  with  this 
and  cooled  to  and  held  at  a  temperature  of  about  700  F.,  until  it 
begins  to  coagulate,  it  will  usually  prove  to  be  a  starter  which  is 
equal,  and  often  superior,  to  a  commercial  starter. 

Commercial  Starters  or  Cultures. — Experiments  have  amply 
proved  that  certain  species  of  bacteria  are  chiefly  responsible 
for  the  butter  flavors  developed  in  cream  during  ripening.  This 
fact  has  given  rise  to  the  use  of  cultures  prepared  in  a  commercial 
way.  These  cultures  contain,  in  a  vigorous  condition,  the  germs 
which  produce  the  desirable  flavors  and  aroma.  The  cultures 
are  put  up  in  laboratories  specially  provided  for  this  kind  of  work. 
Some  of  the  laboratories  put  these  cultures  up  in  liquid  form 
while  others  put  them  up  in  a  dry  or  powder  form.  The  liquid 
starters  consist  of  a  sterile  nutrient  medium,  milk  or  beef  broth, 
inoculated  with  the  culture;  while  the  starters  in  dry  or  powder 
form  are  prepared  by  mixing  the  liquid  culture  with  some  suit- 
able substance,  such  as  milk-sugar,  and  drying  this  mixture  at  a 
temperature  low  enough  not  to  injure  the  germs  present  in  it. 
The  cultures  that  are  put  up  in  the  liquid  form  will  not  keep  so 
long,  and  it  is  not  safe  to  use  them  after  they  are  about  nine  days 
old.  The  cultures  which  are  put  up  in  powder  form  have  the 
advantage  that  they  can  be  kept  for  a  much  longer  time  and  still 
retain  their  vitality.  Both  kinds  as  a  rule  are  good  while  they 
are  fresh.  We  give  a  list  on  next  page  of  the  commercial  cultures 
with  which  the  authors  are  familiar. 

Technically  speaking,  most  of  the  commercial  cultures  sent 
out  from  the  different  laboratories,  to  be  used  in  the  preparation 
of  starters  for  milk-  and  cream-ripening,  are  not  pure  cultures  of 
lactic  acid  organisms,  although  they  are  commonly  spoken  of  as 
such.  A  pure  culture  is  one  which  contains  just  a  single  species 
of  organism,  and  most  of  these  cultures  contain  more  than  one. 
The  commercial  cultures  are,  however,  limited  as  to  variety  of 
species  contained — usually  two  and  at  most  three — and  do  not 


228 


CREAM-RIPENING  AND    STARTERS 


contain  a  promiscuous   variety   of   organisms.     It  is   for   this 
reason  that  they  are  commonly  designated  as  pure  cultures. 


Commercial 
Starters 


Ameri- 
can 


Eoreign 


S.  C.  Keith, 
Charlestown, 
Mass. 
O.  Douglas, 
Boston, 
Mass 
Elov  Ericsson, 
St.  Paul, 
Minn. 
Chr.  Hansen's  Lab- 
oratory, Little 
Falls,  N.  Y. 
Parke, Davis  &  Co., 
Detroit, 
Mich. 
Blauenfeldt  & 
Tvede,  Copen- 
hagen, Den. 
Hjort  &  Fog's 
Laboratory  Cul. 
Copenhagen, 
Den. 
S.  P.  Storm, 
Tillitze,  Naks- 
kov,  Den. 


Lactic  Acid  Culture 
Duplex  Culture 
Boston  Butter  Culture 
Boston  Butter  Culture 
Duplex  Culture 
Lactic  Acid  Culture 

Ericsson's  Butter  Cul- 
ture 


Lactic  Ferment 


Liquid 


Liquid 

Liquid 

and 
Powder 

Powder 


Flavorone 


This  culture  is  put 
up  in  tablet  and 
capsule  forms 


Danish  Lactic 
Acid  Ferment 

Lactic 


Starter 


Powder 


Extensive  work  done  by  Hammer  and  Bailey  of  the  Iowa 
Station  not  only  supports  what  has  just  been  said  regarding 
commercial  cultures,  but  also  goes  to  prove  that  while  the 
organism  which  predominates  in  a  good  culture  or  starter  is  the 
common  lactic  acid  organism  {Streptococcus  lacticus),  there 
must  also  be  associated  with  this,  an  organism  or  organisms, 
which  will  develop  volatile  flavor  and  aroma-producing  acids. 
Hammer  says  that  it  seems  that  there  is  no  longer  any  question 
that  starters  are  mixed  cultures,  and  that  even  a  pure  lactic 
acid  culture  sent  out  from  a  laboratory  very  soon  becomes  a 
mixed  culture  containing  volatile  acid-producing  organisms. 
These  findings  by  Hammer  and  Bailey  are  supported  by  the  work 
done  by  Storch  in  Denmark,  and  Beckout  and  Ott  de  Vries  in 
Holland. 


STARTERS  229 

According  to  Hammer,  the  lactic  acid,  which  is  non-volatile, 
produces  an  acid  flavor  but  very  little  of  the  flavor  and  aroma  so 
characteristic  of  a  good,  well-ripened  cream  and  the  butter  made 
from  it.  The  organisms  which  he  has  found  to  be  the  most 
suitable  associate  organisms  of  the  lactic  acid  organism  {Strep- 
tococcus lacticus)  are  Streptococcus  citrovorus  and  Streptococcus 
paracitrovorus.  S.  citrovorus  acts  upon  the  citric  acid  of  milk 
and  cream  (hence  its  name) ,  and  also  to  a  certain  extent  upon  the 
lactic  acid,  and  converts  these  into  volatile,  flavor-  and  aroma- 
producing  acids.  S.  paracitrovorus,  in  addition  to  performing 
the  same  function,  also  develops  and  uses  another  product. 

A  good  starter  is  one  which  will  develop  a  fair  proportion  of 
the  volatile,  flavor-  and  aroma-producing  acids  without  the 
development  of  an  excess  of  acidity;  that  is,  it  will  afford  all  the 
advantages  to  be  gained  from  the  proper  ripening  of  cream  without 
the  disadvantages  that  come  from  ripening  it  to  too  high  a  degree 
of  acidity.  The  great  problem  is  that  of  the  maintenance  of  a 
proper  balance  between  the  lactic  acid  organism  (S.  lacticus)  and 
the  associate  organism  or  organisms  which  develop  the  volatile, 
flavor-  and  aroma-producing  acids.  One  of  the  large  factors  in 
maintaining  this  balance  is  a  proper  ripening  temperature  in 
both  starter-  and  cream-ripening.  Hammer  mentions  70-7  2°  F. 
as  a  very  favorable  range.  A  temperature  much  above  this  is 
more  favorable  to  S.  lacticus  than  to  S.  citrovorus,  that  is,  it  will 
enhance  the  development  of  lactic  acid  to  a  greater  extent  than 
that  of  the  flavor-  and  aroma-producing  acids,  and  throw  the 
ripening  out  of  balance. 

It  would  seem  then  that  the  big  problem  for  our  laboratories, 
in  the  preparation  of  commercial  cultures,  is  to  supply  a  culture 
which,  if  properly  handled  in  the  creamery,  will  develop  a  reason- 
able amount  of  suitable,  volatile  flavor-  and  aroma-producing 
acids  without  the  development  of  excessive  acidity  in  the  cream ; 
and  that  one  of  the  large  problems  for  the  creameryman  is  proper 
temperature  control  in  both  starter  and  cream-ripening,  so  as  to 
enable  flavor  production  to  keep  pace  with  lactic  acid  produc- 
tion. It  would  seem  to  be  quite  a  safe  practice  to  ripen  the 
cream  at  a  temperature  of  700  F.,  provided  care  is  taken  to  cool 


230  CREAM-RIPENING  AND   STARTERS 

it  early  enough  to  prevent  the  development  of  acidity  from  going 
too  far.  Under  the  varying  conditions  that  exist  in  the  dif- 
ferent creameries  each  creameryman  will  have  to  decide  for 
himself  the  temperatures  that  best  suit  his  conditions.  What 
the  authors  have  aimed  to  do  is  to  state  the  underlying  prin- 
ciples of  successful  starter  and  cream-ripening,  and  what  they 
would  urge  most  is  the  intelligent  application  of  these  prin- 
ciples. 

Preparation  of  Commercial  Starters. — All  of  the  starters 
mentioned  above  have  been  tested  and  are  known  to  produce 
good  results.  The  first  step  in  the  preparation  of  a  mother- 
starter  (starterline)  is  to  prepare  preferably  a  glass  jar  or  bottle 
by  thoroughly  cleaning  and  sterilizing  it.  Glass  jars  are  used  in 
preference  to  any  other  vessel,  because  if  they  are  unclean  in  any 
way,  it  will  be  apparent.  Secondly,  there  are  no  seams  and  no 
places  on  the  inside  which  will  corrode,  and  in  that  way  retain 
unnoticeable  dirt;  and  in  the  third  place,  the  nature  of  the  coag- 
ulation can  be  readily  observed  through  the  glass.  Mason  jars 
and  sampling  bottles  are  suitable.  The  kind  of  bottle  which 
is  used  for  marketing  milk  gives  very  good  results. 

The  second  step  consists  in  selecting  suitable  milk.  The 
milk  must  be  in  as  pure  and  sweet  a  condition  as  possible.  A 
good  starter  can  be  produced  from  either  whole  or  skim-milk. 
At  one  time  skim-milk  was  given  a  decided  preference  for  use  in 
the  making  of  starters.  But  the  views  of  some  of  our  leading 
bacteriologists  and  practical  creamerymen,  experienced  in  the 
preparation  and  use  of  starters,  have  changed  upon  this  point 
and  they  now  express  a  decided  preference  for  the  use  of  whole 
milk  starters.  The  reasons  for  this  preference  may  be  briefly 
stated:  The  whole  milk  is  generally  more  easily  selected;  it 
is  the  practice  in  some  of  our  best  creameries  to  have  some 
farmer  supply  milk,  produced  under  special  sanitary  conditions 
and  cooled  promptly  to  a  low  temperature,  for  starter  purposes. 
The  trouble  of  separating  and  a  possible  extra  source  of  contam- 
ination are  avoided.  The  presence  of  the  fat  in  the  milk  serves 
two  useful  purposes;  first,  the  cream  that  rises  seals  the  starter 
over  and  prevents  contamination,  and  second,  the  exclusion  of 


STARTERS 


231 


air  prevents  the  development  of  certain  injurious  organisms, 
which  may  be  present  and  which  require  air  for  growth. 

However,  fine  starters  can  be  made  from  either  whole  milk  or 
skim-milk,  and  the  point  of  first  importance  is  that  the  milk 
used  be  sweet  and  in  a  clean,  sanitary  condition. 

The  milk  which  has  been  selected  for  the  mother-starter,  or 
starter  line,  is  then  pasteur- 
ized. The  pasteurization  is 
best  accomplished  by  the 
intermittent  method.  If 
considerable  milk  is  to  be 
pasteurized  it  is  best  to 
make  use  of  a  clean,  steril- 
ized starter  can.  If  only  a 
small  portion  is  to  be  pas- 
teurized, just  enough  for  the 
mother-starter,  the  milk  can 
be  put  directly  into  the  jars. 
The  jar  half  full  is  about  the 
proper  amount  of  milk  to 
use.  The  directions  sent 
with  some  pure  cultures 
recommend  as  much  as  half 
a  gallon  or  a  whole  gallon 
of  milk.  As  a  rule  better 
results  are  obtained  if  only 
about  a  pint  of  milk  is 
taken.  If  the  milk  for  the 
mother-starter  is  pasteur- 
ized in  the  glass  bottles 
or  jars,  it  is  advisable  to  set  the  bottles  containing  the  milk 
into  cold  water, — covering  the  jar  so  as  to  prevent  outside  con- 
tamination,— and  then  heat  up  the  water  gradually.  Care 
should  be  taken  not  to  insert  these  bottles  suddenly  into  scalding 
hot  water,  or  to  let  the  steam  strike  them,  for  either  is  likely  to 
crack  the  bottles.  Care  should  be  taken  also  to  exclude  water 
from  milk  used  for  starters.     It  is  advisable  to  heat  this  milk,  for 


Fig.  80.  —  An  Incubating  Chamber  for 
Starters.  The  inner  compartment  will 
hold  a  pail  of  water  and  the  bottles  for 
the  mother-starters.  The  temperature 
can  be  kept  at  any  desired  point  by  the 
use  of  warm  or  cold  water.  The  four- 
inch  space  between  the  walls  is  filled  with 
hay  or  mineral  wool.  (Dairy  Bac- 
teriology, Russell  and  Hastings.) 


232  CREAM-RIPENING  AND   STARTERS 

the  starterline,  as  high  as  possible  in  hot  water,  say  up  to  about 
200 °  F.  The  sample  may  assume  a  cooked  taste,  but  this  will 
soon  disappear  after  the  starter  has  been  carried  on  a  few 
days.  The  milk  should  be  left  at  this  high  temperature  for 
about  ten  or  fifteen  minutes.  A  longer  time  does  no  harm. 
Then  the  milk  is  gradually  cooled  to  about  8o°  F.  This  high 
temperature  is  desirable,  because  the  germs  present  in  the 
commercial  culture  may  be  somewhat  dormant.  This  high 
temperature  would  tend  to  revive  them  more  quickly  than  a 
lower  temperature.  Great  care  should  always  be  taken  to 
cool  the  milk  previous  to  inoculating  it  with  the  pure  culture, 
otherwise  the  germs  present  in  the  culture  will  be  destroyed. 

Inoculation. — The  next  step  is  to  inoculate  the  prepared 
milk  with  the  culture  obtained  from  the  laboratory.  The 
bottle  which  contains  the  culture  is  carefully  opened,  turned 
over  and  emptied  into  the  pasteurized  milk.  It  should  be 
held  down  closely  to  the  mouth  of  the  jar  containing  the 
sterile  milk,  in  order  to  prevent,  as  far  as  possible,  the  entrance 
of  the  air  and  the  consequent  danger  of  contamination.  Then 
the  milk  containing  the  culture  is  thoroughly  stirred  and  set 
away  in  a  room  where  the  temperature  is  about  700  F.  This 
will  gradually  cool  the  milk  from  8o°  to  700  F.,  and  in  about 
twenty  to  forty  hours  the  milk  will  sour  and  coagulate.  Germs 
in  nearly  all  of  the  liquid  cultures  are  rather  slow  in  acting  upon 
the  milk,  undoubtedly  due  to  the  dormancy  of  the  germs,  and  to  a 
comparatively  few  of  them  being  present  in  the  culture.  When 
the  powdered  cultures  are  used,  a  little  more  care  is  essential  to 
get  the  powder  thoroughly  mingled  with  the  milk.  It  is  a  trifle 
more  difficult  to  get  the  powder  thoroughly  mixed  with  the  milk 
than  it  is  to  get  the  liquid  cultures  mixed.  If  anything  is  used 
with  which  to  stir  the  sample,  it  should  be  sterilized  before  com- 
ing in  contact  with  the  milk.  This  applies  in  the  preparation  of 
all  cultures.  In  testing  or  sampling  the  mother-starter,  nothing 
should  be  allowed  to  come  in  contact  with  it  unless  it  has  pre- 
viously been  thoroughly  sterilized.  The  powder  cultures  are 
usually  more  vigorous  in  their  effect  than  most  of  the  liquid 
cultures   now   on   the   market.     The   powder   cultures   usually 


STARTERS  233 

coagulate  the  sample  in  about  twenty-four  hours,  and  if  the 
operator  is  used  to  handling  the  liquid  cultures,  he  should  watch 
the  mother-starters  prepared  from  powder  cultures,  so  that  they 
do  not  get  overripe.  It  is  very  essential  that  this  should  not 
happen.  The  time  when  the  germs  are  most  numerous  and 
most  active  in  the  starter  is  about  the  time  when  the  sample 
coagulates.  As  soon  as  this  stage  has  been  reached,  or  just 
previous  to  coagulation,  the  starter  should  be  cooled  down 
to  at  least  500  F.,  or  lower  if  possible.  This  prevents  any 
further  growth  of  germs  and  the  sample  can  thus  be  kept  a  short 
time  without  injury. 

Directions  usually  accompany  each  of  the  cultures,  but  the 
above  will  be  found  to  produce  good  results  with  all  of  those 
mentioned  in  the  above  list. 

By  putting  from,  2  per  cent  to  5  per  cent  or  more  of  the 
mother-starter  into  a  large  sample  of  pasteurized  milk,  any 
desired  amount  of  starter  can  be  prepared.  In  selecting  this 
amount  of  milk,  as  much  care  as  possible  should  be  taken  in 
order  to  select  the  best  kind  of  milk,  and  keep  it  from  being  con- 
taminated. When  this  large  sample  of  starter  is  at  the  proper 
stage  of  coagulation,  it  should  be  used  at  once,  or  else  cooled 
down  to  about  500  F.  The  amount  of  mother-starter  with 
which  to  inoculate  the  large  sample  of  starter  may  vary  a  little 
without  any  bad  effects.  If  the  large  sample  of  starter  is  to 
be  ready  for  use  in  a  short  time,  a  larger  portion  of  the  mother- 
starter  can  be  used  for  inoculation.  If  the  temperature  at 
which  the  starter  is  set  and  the  amount  of  mother-starter  used 
for  inoculation  are  the  same  from  day  to  day,  the  starter  will 
be  ripe  at  nearly  the  same  hour  every  day,  and,  consequently, 
more  uniform  ripening  results  can  be  obtained.  The  noticeable 
coagulation  of  the  starter  when  milk  or  skim-milk  is  used  will 
usually  take  place'  when  there  is  about  .6  per  cent  of  acidity. 
A  slight  coagulation  will  take  place  when  there  is  about  .5  per 
cent  of  acidity,  but  it  is  hardly  noticeable.  The  coagulation- 
point  may  vary  with  different  samples  of  milk. 

If  a  mother-starter  is  to  be  kept  any  length  of  time  it  should 
be  inoculated  into  a  sample  of  good  fresh  pasteurized  milk  about 


234  CREAM-RIPENING  AND  STARTERS 

every  other  day.  If  a  mother-starter,  or  starter  of  any  kind, 
is  allowed  to  stand  too  long  at  a  low  temperature,  the  desirable 
germs  will  become  dormant,  and  some  undesirable  germs  will 
gradually  gain  a  foothold.  It  is  a  good  plan  to  carry  any  mother- 
starter  along  for  two  or  three  days  before  it  is  used  to  inoculate 
a  large  sample  of  milk.  When  the  mother-starter  is  first  pre- 
pared it  sometimes  possesses  an  undesirable  taste  and  smell  from 
the  medium  in  which  the  germs  were  put  up  at  the  laboratory. 
This  smell  and  taste  are  eliminated  by  carrying  it  on  two  or 
three  days  previous  to  its  use. 

After  inoculation  and  the  proper  mixing  of  the  mother- 
culture  with  it,  a  new  starter  should  not  be  disturbed  during 
the  ripening  process.  A  good  starter,  when  ready  for  use,  will 
have  a  soft,  close  coagulation,  without  any  gas  openings  or 
wheying  off  (particularly  at  the  bottom);  it  will,  when  mixed, 
break  up  readily  and  form  a  smooth,  creamy  liquid  entirely  free 
of  lumps,  and  will  possess  a  pleasant  acid  taste  and  a  character- 
istic aroma  that  is  delicate  and  agreeable. 

It  is  of  vital  importance  that  a  starter  be  prepared  and  kept 
in  specially  sanitary  surroundings.  While  not  absolutely  essen- 
tial, it  is  advisable,  if  possible,  to  have  a  small  room,  suitably 
constructed  and  equipped,  as  a  starter  room.  The  chief  equip- 
ment of  such  a  room  would  consist  of, 

(i)  Quart  sealers  or  bottles  in  which  to  prepare  the  mother- 
culture  from  day  to  day. 

(2)  A  small  galvanized  iron  tank  or  box  in  which  to  sterilize 
bottles,  thermometers,  dippers,  etc.  It  should  have  water 
and  steam  connections. 

(3)  A  small  incubating  chamber  in  which  to  keep  the  mother- 
starters.  This  is  a  small  insulated  box  or  chamber  lined  with 
galvanized  iron  and  well  insulated  so  that  the  temperature 
can  be  kept  at  any  point  desired. 

(4)  A  suitable  starter  can,  one  of  suitable  size,  in  which 
heating  and  cooling  can  be  accomplished  readily,  and  which  is 
well  insulated  so  as  to  hold  temperature. 

One  of  our  largest  creamery  companies,  a  company  whose 
butter  has  won  an  enviable  reputation  in  the  New  York  and  other 


STARTERS  235 

eastern  markets,  follows  a  system  of  handling  and  ripening 
cream,  in  all  of  its  creameries,  which  is  worthy  of  consideration. 
The  acidity  of  the  cream  is  reduced  to  about  150  Mann's_Test 
(.27  per  cent)  for  pasteurization,  milk  of  lime  being  the  neu- 
tralizer  used.  The  cream  is  then  pasteurized  at  a  high  tem- 
perature, 1800  to  185 °  F.,  after  which  it  is  promptly  cooled  to 
ripening  temperature.  Before  adding  the  starter  the  acidity 
is  further  reduced  to  50  to  8°,  Mann's  (.09  to  .14  per  cent), 
if  it  has  not  already  fallen  to  this  during  pasteurization.  If 
there  be  any  probability  of  trouble  with  metallic  flavor  the 
acidity  is  reduced  still  lower — to  20  or  30,  Mann's  test  (.04  or 
.05  per  cent).  A  carefully  prepared  starter,  which  is  active 
and  possesses  a  desirable,  clean  flavor,  is  then  added,  and  the 
cream  is  ripened  and  held  overnight.  The  aim,  in  ripening 
the  cream,  is  to  develop  an  acidity  of  about  300  Mann's  (.50  to 
.55  per  cent)  for  churning. 

Great  care  is  exercised  in  connection  with  the  raw  material 
and  the  preparation  and  use  of  the  starter,  and  equal  care  is 
taken  to  avoid  subsequent  contamination  of  the  cream,  due  to 
faulty  or  unclean  pipes  or  utensils.  As  to  the  raw  material  for 
the  starter,  the  practice  is  to  arrange  with  some  farmer  to 
supply  milk  produced  under  special  sanitary  conditions,  and 
promptly  cooled  and  held  at  a  low  temperature  until  shipped.  A 
special  room  is  fitted  up  as  a  starter-room  and  this  is  placed  in 
the  charge  of  a  man  skilled  in  the  preparation  and  use  of  starters. 

The  butter  made  from  cream,  handled  and  ripened  as  indi- 
cated, possesses  not  only  a  fine,  full  flavor  and  aroma  when 
made,  but  good  keeping  qualities  as  well.  The  butter  made 
by  this  company  commonly  sells  at  a  substantial  premium  over 
Extras  and  Specials. 

Milk  Powder  for  Starters. — According  to  experiments  con- 
ducted at  the  South  Dakota  Experiment  Station,  Bui.  123, 
milk  powder  solutions  may  be  successfully  used  instead  of  the 
natural  milk  for  starters. 

In  many  large  central  creameries,  skim-milk  is  difficult  to  ob- 
tain.   In  such  places  milk  powder  can  be  and  is  successfully  used. 

Milk  powder  is  of  about  the  same  consistency  as  flour  and 


236  CREAM-RIPENING  AND  STARTERS 

dissolves  in  cold  water  with  similar  difficulty.  To  make  the 
milk  powder  dissolve  as  quickly  as  possible,  weigh  out  the 
required  amount  of  water  into  the  starter  can.  Turn  the  steam 
on  and  heat.  While  the  water  is  heating  weigh  out  the  required 
amount  of  milk  powder.  Use  powder  at  the  rate  of  3  ounces  to 
1  quart  of  water.  Add  the  milk  powder  to  the  water  and  stir 
violently.  If  little  lumps  remain  stir  every  five  or  ten  minutes 
during  heating.  Continue  to  heat  or  pasteurize  as  though  it 
were  normal  milk.  The  remainder  of  the  processes  involved 
in  making  this  into  a  starter  are  the  same  as  already  described. 

Length  of  Time  a  Starter  Can  be  Carried. — In  this  country, 
even  if  special  precautions  are  taken,  it  seems  almost  impossible 
to  carry  on  a  starter  for  more  than  four  weeks  without  having 
undesirable  ferments  enter.  The  length  of  time  a  starter  can  be 
carried  undoubtedly  depends  upon  conditions,  and  the  care 
with  which  it  has  been  handled.  When  a  starter  is  properly 
prepared,  cooled  gradually  before  coagulation,  and  not  over- 
ripened,  it  will  contain  a  smooth  soft  curd,  and  retain  its  mild 
acid  flavor  for.  at  least  a  month  The  Danes,  who  use  starters  in 
butter-making  more  regularly  than  any  other  people,  are  able  to 
carry  a  starter  along  for  six  months  or  more  without  renewing  it. 

It  is  a  good  plan  to  keep  at  least  two  different  kinds  of  starter 
by  carrying  them  on  from  day  to  day  in  small  quart  jars.  Then  if 
one  should  happen  to  "  go  off,"  the  other  one  can  be  used  instead. 

Poor  Starters. — Many  unsuccessful  results  from  the  use  of 
starters  for  cream-ripening  have  been  reported.  The  failure 
can  be  traced  to  the  improper  use  of  starters.  If  starters  are 
good  they  will  never  bring  about  poorer  results  than  are  obtained 
without  the  use  of  them.  Owing  to  the  fact  that  it  is  difficult 
to  keep  the  same  starter  in  a  good  condition  very  long,  many 
starters  are  used  which  develop  abnormal  fermentations  in  cream. 
A  slightly  acid,  somewhat  bitter  taste,  and  a  slimy  condition  of 
the  starter  are  defects  which  are  very  common.  These  condi- 
tions seem  to  be  brought  about  chiefly  by  overripening  it  at  a 
high  temperature,  and  keeping  it  a  long  time  at  a  low  tempera- 
ture before  using  it.  Slimy  fermentation  is  very  common  in 
starters  which  have  been  carried  on  for  a  time.     Whenever  this 


STARTERS  237 

slimy  ferment  develops  in  the  starter  it  can  be  noticed  both  in 
the  cream  and  in  the  starter  by  the  failure  of  the  acid  to  develop 
so  rapidly  as  when  the  proper  acid-producing  ferment  is  present. 
It  seems  almost  impossible  to  develop  any  more  than  about  .5 
per  cent  of  acidity  in  30  per  cent  cream,  while  if  the  proper  fer- 
ment were  present,  about  .7  per  cent  could  be  developed.  A 
decrease  in  the  quality  of  butter  accompanies  the  development 
of  this  ferment  in  the  cream. 

Whenever  it  is  found  that  a  starter  is  not  in  good  condition, 
it  should  not  be  used,  as  a  poor  starter  is  worse  than  none  at  all. 
The  buttermilk  from  the  previous  cream  can  sometimes  be  used 
advantageously  until  a  new  starter  can  be  prepared. 

Underripening  and  Overripening  of  Starters. — The  effect  of 
overripening  starters  has  already  been  mentioned  under  the 
"  Preparation  of  Mother-starters."  The  question  of  under- 
ripening  starters  is  also  of  importance.  It  is  a  well-known  fact 
that  just  about  the  time  when  the  milk  begins  to  turn  sour, 
that  is,  when  the  sourness  can  just  be  recognized  by  the  taste, 
it  has  a  rather  disagreeable  flavor.  After  more  acid  develops 
the  undesirable  flavor  largely  disappears,  and  the  milk  assumes 
a  clean,  desirable  acid  taste.  The  reasons  for  this  have  been 
stated  by  S torch,  the  well-known  authority  on  starters.  He 
claims  that  this  disagreeable  flavor  is  due  to  the  action  of  unde- 
sirable organisms,  during  the  first  souring  stage.  As  the  souring 
progresses  these  germs  are  subdued  and  gradually  crowded  out 
by  the  desirable  acid-producing  types. 

In  the  preparation  of  a  starter  the  probabilities  are  that 
some  of  these  undesirable  types  of  germs  are  present.  At  least 
"it  is  safer  to  go  on  the  assumption  that  they  are  present.  This 
makes  the  underripening  of  starters  just  as  important  to  guard 
against  as  overripening. 

Amount  of  Starter  to  Use. — The  amount  of  starter  will  vary 
under  different  conditions.  It  may  vary  from  none  at  all  to 
as  much  as  50  per  cent  of  the  cream  to  be  ripened.  The  quality 
of  cream  is  one  of  the  factors  that  need  to  be  considered.  Raw 
cream  and  old  cream  both  require  a  large  starter,  especially  if 
the  cream  is  thick  enough  to  permit  of  being  reduced  in  thick- 


238 


CREAM-RIPENING  AND   STARTERS 


ness.     Good  pasteurized  cream  does  not  need  a  larger  starter 
than  about  10  per  cent  of  the  cream  to  be  ripened. 

The  amount  of  starter  to  use  also  depends  somewhat  upon 
the  general  creamery  conditions.  In  some  creameries  all  the 
cream  is  received  in  a  very  sour  and  poor  condition,  and  facilities 
for  getting  milk  for  preparation  of  starters  are  often  very  poor. 
Under  such  conditions  it  is  questionable  whether  it  would  be 
profitable  to  use  starters  at  all.  The  amount  of  starter  to  use 
chiefly  depends  upon  the  degree  of  rapidity  of  ripening  desired, 
and  upon  the  temperature  of  the  cream.  If  it  is  desirable  to 
ripen  quickly,  a  comparatively  large  amount  of  starter  (15  per 
cent  to  25  per  cent)  should  be  added,  and  the  ripening  tempera- 
ture should  be  comparatively  high  (about  700  to  740  F.)  if  slow 
ripening  is  desired,  less  starter  may  be  used.  Enough,  however, 
should  be  used  to  control  the  fermentation  in  the  cream  (about 
10  per  cent  to  15  per  cent),  and  the  ripening  temperature  may  be 

lower,  between  6o°  and  700  F.  More 
starter  should  be  used  in  the  winter. 
Use  of  Starter-cans. — In  the  past, 
ordinary  tin  shot-gun  cans  have  been 
used  in  most  cases  for  the  prepara- 
tion of  starters,  and  have  given  good 
results.     Some  makers  still  use  such 


cans. 

The  earliest  starter-cans  were 
made  of  light  material  and  did  not 
last  long.  These  defects,  however, 
have  largely  been  done  away  with, 
and  the  use  of  starter-cans  certainly 
is  an  improvement  over  the  old 
method  of  preparing  the  starters  in 

Fig.  81.— Improved  Victor  Starter   several  smaller  cans. 

(Creamery  Package  Mfg.  These  starter-cans  are  jacketed, 
so  that  the  temperature  can  be  con- 
trolled by  using  hot  or  cold  water,  or  ice,  as  demanded,  in 
the  jacket.  All  of  the  starter-cans  have  an  agitator,  which  is 
operated  with  a  belt. 


Can. 

Co.) 


CHAPTER  XVII 
CHURNING  AND  WASHING  BUTTER 

Definition. — By  churning  we  understand  the  agitation  of 
cream  to  such  an  extent  as  to  bring  the  fat-globules  together 
into  masses  of  butter  of  such  size  as  to  enable  the  maker  to  sep- 
arate them  from  the  buttermilk. 

The  agitation  may  be  brought  about  in  several  different  ways, 


Fig.  82. — Ancient  method  of  churning 
in  skin  bags. 


Fig.  83. — The  Dash  churn. 


and  by  different  shaped  devices,  which  are  called  churns.  The 
methods  of  churning,  like  the  process  of  separation,  began  with 
primitive  methods.  The  ancients  churned  their  milk,  without 
separation,  in  bags  made  from  the  skins  of  animals.  The  next 
step  in  advance  was  to  place  milk  or  cream  in  bottles  or  jars,  and 
then  to  shake  them.  This  latter  method  of  churning  cream  in 
bottles  is  yet  in  use  in  many  of  the  smaller  households  of  Europe, 
where  the  amount  of  cream  is  limited  to  a  small  quantity  donated 

239 


240  CHURNING  AND  WASHING  BUTTER 

by  cow-owners.  The  next  step  toward  churning  on  a  large 
scale  was  to  get  a  large  wooden  box  or  barrel  run  by  power  or  by 
hand.  The  churns  which  are  in  use  at  the  present  time  in 
American  butter-factories  are  termed  "  combined  churns." 
They  are  so  arranged  as  to  admit  of  churning,  washing,  salting, 
and  working  without  removing  the  butter  from  the  churn.  This 
style  of  churn  is  now  being  introduced  into  Europe.  Owing 
to  their  superior  worth  they  will  soon  be  in  general  use  there  as 
well  as  here.  They  keep  flies  away  from  the  butter  during  fly 
time;  the  temperature  of  the  butter  can  be  controlled  in  the 
churn,  and  the  handling  of  the  butter  during  salting  and  working 
is  obviated. 

CONDITIONS  AFFECTING  THE  CHURNABILITY  OF  CREAM 

Temperature. — The  temperature  of  cream  is  one  of  the  most 
influential  factors  in  determining  its  churnability.     The  higher 


Fig.  84.  -  Dual  Churn  (Creamery  Package  Mfg.  Co.) 

the  temperature  of  the  cream,  the  sooner  the  churning  process 
will  be  completed.  Too  high  a  churning  temperature,  however, 
is  not  desirable.  It  causes  the  butter  to  come  in  soft  lumps 
instead  of  in  a  flaky  granular  form.  This  is  deleterious  to  the 
quality  of  the  butter.  It  causes,  first,  a  greasy  texture  of  the 
butter,  and,  second,  the  incorporation  in  the  butter  of  too  much 
buttermilk.     This  buttermilk  contains  sugar,  curd,  and  water, 


CONDITIONS    AFFECTING    THE    CHURNABILITY    OF    CREAM       241 


which,  when  present  together  in  butter,  are  likely  to  sour  and  in 
other  ways  injure  the  butter.  Curd  and  sugar  should  be 
excluded  from  butter  as  much  as  possible,  in  order  to  eliminate 
food  for  bacteria  which  may  be  present. 
An  excess  of  curd  is  also  favorable  to 
the  formation  of  mottles.1 

Too  low  a  temperature  is  also  un- 
desirable, although  it  is  better  to  have 
the  temperature  a  little  low  rather  than 
too  high.  When  the  churning  tempera- 
ture is  too  low,  difficult  churning  is 
likely  to  occur.  Cream  at  a  low  tem- 
perature becomes  more  viscous.  On 
agitation  in  the  churn  such  cream,  if  it  is 

very  thick,  will  adhere  to  the  sides  of  the  churn  and  rotate  with  it 
without  agitating;  consequently  no  churning  will  take  place. 
Too  low  a  temperature  brings  the  butter  in  such  a  firm  condi- 
tion that  it  takes  up  salt  with  difficulty,  and  when  this  hard 


Fig.  85. 


Sectional  view  of 
Dual. 


Fig.  86. — Perfection  Dreadnaught  Churn  (J.  A.  Cherry  Co.) 


butter  is  being  worked,  a  large  portion  of  the  water  in  the 
butter  is  expressed,  and  the  overrun  will  be  lessened  to  a  great 
extent  without  increasing  the  commercial  value  of  the  butter. 

The  degree  of  hardness  of  the  fat  in  the  cream  is  the  govern- 
ing factor  in  deciding  the  churning  temperature.     The  churning 

1  Bui.  No.  263,  Geneva,  N.  Y. 


242 


CHURNING  AND  WASHING  BUTTER 


temperature  will  vary  a  great  deal  in  different  localities.  The 
hardness  of  the  fat  depends  upon  (i)  the  season  of  the  year; 
(2)  the  individuality  of  cow;  (3)  the  stage  of  lactation;  and  (4) 
the  kind  of  food  fed  to  the  cows.     All  these  factors  influence  the 

melting-point  of  butter-fat.  The 
higher  the  melting-point  of  the 
butter-fat  is,  the  higher  the  churn- 
ing temperature,  and  the  lower  the 
melting-point  of  the  fat,  the  lower 
the  churning  temperature. 

1.  During  the  spring  the  cows 
yield  milk  containing  a  larger  pro- 
portion of  soft  fats;  consequently 
the  churning  temperature  is  always 
lower  in  the  spring  than  in  the  fall 
or  winter.  During  winter,  when 
the  cows  are  fed  on  dry  food  chiefly, 
the  harder  fats  increase  in  quantity,  and  consequently  a  higher 
churning  temperature  is  necessary  during  that  time. 


Fig. 


87. — Sectional  view  of  Perfec- 
tion working  butter. 


Pig.  88.-  Disbiow  churn  (Davis-Watkins  Dairymen's  Mfg.  Co.) 


2.  Some  animals  produce  milk  containing  a  larger  propor- 
tion of  softer  fats  than  do  other  animals.  It  is  said  that  the 
difference  in  this  respect  is  more  marked  in  certain  breeds.  It 
is  maintained  that  the  cows  of  the  Jersey  breed  produce  milk 


CONDITIONS    AFFECTING    THE    CHURNABILITY    OF    CREAM     243 


Fig.  89. — Sectional  view  of  Disbrow. 


containing  a  larger  proportion  of  the  softer  fats  than  do  those  of 
any  of  the  other  breeds. 

3.  The  period  of  lactation  also  affects  the  melting-point  _of 
butter-fat.  When  a  cow  is  fresh  she  yields  a  larger  proportion 
of  the  soft  fats  than  she  does 
later  on  in  the  lactation  period. 
Just  how  much  this  change  in 
the  hardness  of  the  fat  is  due 
to  advance  in  the  lactation 
period  and  how  much  to 
change  from  succulent  to  dry 
feeds  is  not  definitely  known, 
since  the  two  parallel  each 
other  so  closely,  it  being  the 
common  practice  in  this  coun- 
try to  have  the  cows  freshen 
in  the  spring.  According  to 
investigations  conducted  at  the  Purdue  Station,1  the  melting 
point  of  the  fat  lowers  as  a  cow  advances  in  her  lactation  period, 
provided  she  is  fed  the  same  feeds  throughout  the  year.  If 
these  findings  be  correct,  they  mean  that  the  influence  of  the 
feed  is  much  greater  than  that  of  the  stage  of  lactation,  since  the 
broad  truth  still  remains,  that  under  our  conditions  the  propor- 
tion of  hard  fats  increases  as  the  lactation  period  advances. 
Witn  this  increase  in  the  proportion  of  the  hard  fats  in  the 
advancement  of  the  lactation  period,  the  fat-globules  become 
smaller.  This,  together  with  the  increased  hardness  of  the  fat, 
causes  difficult  churning  at  times.  It  readily  can  be  seen  that 
the  larger  the  fat-globules  are  the  greater  are  the  chances  for 
these  globules  to  strike  each  other  during  agitation  in  the  churn- 
ing process. 

4.  The  nature  of  the  food  fed  affects  the  melting-point  of 
butter  to  a  considerable  extent.  Cotton-seed  and  its  by-products 
have  been  demonstrated  thoroughly  by  several  investigators  to 
cause  butter  to  become  hard.  When  a  large  amount  of  cotton- 
seed is  fed,  the  butter  assumes  a  crumbly,  tallowy,  hard  condi- 

1  Purdue  Bulletin  159. 


244 


CHURNING  AND   WASHING  BUTTER 


tion;  while  linseed  meal,  and  practically  all  succulent  foods,  tend 
to  decrease  the  melting-point  of  butter-fat. 

According  to  the  above  it  can  be  concluded  that  the  churning 


Fig.  90. — Master  dual  churn  (Creamery  Package  Mfg.  Co.) 

temperature  may  vary  between  wide  limits,  but  the  average 
desirable  churning  temperature  under  normal  conditions  is 
between  500  and  6o°  F.     It  may,  and  does,  go  outside  these 

limits  at  times;  for  in- 
stance, many  cream- 
eries find  it  necessary 
to  churn  at  a  tempera- 
ture under  500  F.  in 
the  early  part  of  the 
summer  season,  when 
the  grass  is  very  young 
and  succulent  and  the 
proportion  of  soft  fats 
is  very  high.  Any  con- 
m  TT  „      „  0  „  N      ditions   which  tend  to 

-Simplex  churn  (D.  H.  Burrell  &  Co.) 

harden  the  butter-fat 
will  require  a  comparatively  high  churning  temperature;  and 
any  conditions  tending  to  soften  the  butter-fat  will  require  a 


Fig.  91. 


CONDITIONS    AFFECTING    THE    CHURNABILITY    OF    CREAM     245 

lowering  of  the  churning  temperature.  The  lower  the  tempera- 
ture at  which  the  churning  can  be  successfully  accomplished,  the 
more  complete  will  be  the  churning;  that  is,  the  less  fat- will 
remain  in  the  buttermilk. 

Influence  of  Length  of  Time  Held  at  Churning  Temperature. — 
The  length  of  time  that  cream  is  held  at  the  churning  tempera- 
ture is  a  factor  that  must  be  considered.  If  it  be  found  necessary 
to  churn  cream  soon  after  cooling  it,  it  should  be  cooled  to  a 
lower  temperature  than  would  otherwise  be  necessary.  Cream 
should  be  held  at  least  two  hours  at  churning  temperature  before 
it  is  churned — better  a  longer  time.  It  takes  this  length  of  time 
at  least  for  the  fat,  which  is  a  poor  conductor  of  heat  and  firms 
slowly,  to  reach  the  temperature  of  the  serum  of  the  cream  and 
become  firm. 

In  the  same  creamery,  with  cream  of  the  same  richness,  we 
have  observed  that  cream  churned  immediately  after  cooling 
would  churn  as  readily  at  51  °  to  520  F.  as  cream  held  at  560  F. 
overnight  and  churned  without  change  of  temperature.  The 
per  cent  of  fat  was  much  lower  in  the  buttermilk  from  the  cream 
held  overnight  than  it  was  in  that  from  cream  churned  soon  after 
being  cooled. 

Richness  of  Cream. — The  amount  of  fat  in  the  cream  affects 
the  churnability  of  it  considerably.  The  richer  the  cream  the 
sooner  will  the  churning  be  completed,  that  is,  providing  the 
cream  is  not  rich  enough  to  be  so  thick  as  to  cause  it  to  adhere 
to  the  inside  of  the  churn  and  thus  escape  being  agitated.  If 
rich  cream  is  churned  at  a  high  temperature  the  butter  will  come 
in  a  remarkably  short  time,  providing  all  other  conditions  are 
favorable .  Thin  cream  churns  much  more  slowly,  and  can  be 
churned  at  a  higher  temperature  than  thick  cream,  without 
injuring  the  quality  of  the  butter.  When  rich  cream  is  churned 
at  a  high  temperature,  and  the  butter  cqmes  in  a  short  time 
(about  ten  minutes),  the  butter  will  usually  be  greasy  in  body, 
and  will  contain  a  great  deal  of  buttermilk,  which  will  be  more 
or  less  difficult  to  remove  on  washing.  When  thick  cream  is 
being  churned,  the  butter  does  not  break  in  the  form  of  small 
round  granules,  as  it  does  when  thin  cream  is  churned. 


246 


CHURNING  AND  WASHING  BUTTER 


When  thick  cream  is  churned  at  as  high  a  temperature  as  is 
consistent  with  getting  a  good  texture,  the  best  results  are 
obtained.     In  the  first  place,  rich  cream  produces  less  butter- 


Fig.  92.— Victor  heavy  duty  churn  (Creamery  Package  Mfg.  Co.) 


milk,  consequently  less  fat  will  be  lost  in  the  buttermilk.  This 
would  tend  to  increase  the  overrun.  Secondly,  the  breaking 
of  the  butter  at  the  end  of  the  churning  will  be  such  as  to  cause 

the  granules  to  appear  large  and  flaky, 
rather  than  small  and  round.  The 
more  flaky  granules  of  butter  will 
retain  more  moisture  than  the  smaller, 
harder  granules  under  the  same  treat- 
ment. Experiments  show  that  when 
different  thicknesses  of  cream  (thin 
cream  containing  on  an  average  22  per 
cent  of  fat,  and  thick  cream  36  per 
cent  of  fat)  are  churned,  there  is  a  dif- 
ference of  about  3  per  cent  in  the  mois- 
ture-content of  the  butter.  The  aver- 
age churning  temperatures  of  cream  and  wash-water  in  these 
experiments  were  56  °  and  53  °  F.  respectively. 

When  thick  cream  is  churned,  and  the  temperature  is  mod- 


Fig.  93. — Sectional  view  of 
four  roll  Victor  working 
butter. 


CONDITIONS    AFFECTING    THE    CHURNABILITY    OF    CREAM     247 

erately  high,  it  is  almost  impossible  to  churn  the  butter  into 
granules.     This  condition  causes  butter  from  thick  cream  to 

contain  more  moisture  than  butter  from  thin  cream.  - 

Amount  of  Cream  in  Churn. — When  the  churn  is  about  one- 
third  full,  the  greatest  degree  of  agitation  is  obtained,  and  con- 
sequently a  quicker  churning.  If  a  small  amount  of  cream  is 
being  churned,  it  is  often  difficult  to  gather  the  butter  properly. 


Fig.  94. — Danish  churns  and  frame  for  holding  them. 


If  the  cream  is  thin,  the  granules  are  thrown  about  in  such  a 
way  that  they  are  gathered  with  difficulty.  If  the  cream  is 
thick,  the  small  amount  of  cream  will  adhere  to  the  inside  of  the 
churn,  and  in  that  way  delay  the  completion  of  the  churning. 
It  is  a  common  opinion  that  less  overrun  is  obtained  from 
a  small  churning  than  from  a  large  churning.  It  is  safe  to  say 
that  if  it  were  possible  to  maintain  all  conditions  alike,  especially 
as  to  temperature  and  degree  of  churning,  there  would  be  very 


248  CHURNING  AND  WASHING  BUTTER 

little  difference  in  the  moisture-content  of  the  butter  made  from 
churnings  of  different  sizes.  When  there  is  only  a  small  amount 
in  the  churn,  the  atmospheric  temperature  is  likely  to  raise  or 
lower  the  temperature  of  the  cream.  If  the  atmosphere  is 
warm,  then  the  butter  from  the  small  churning  is  more  likely 
to  be  soft.  A  small  amount  of  cream  in  the  churn  is  also  more 
likely  to  be  over  churned  than  a  larger  amount  of  cream.  These 
two  factors  would  tend  to  increase  the  amount  of  water  in  the 
butter.  In  mixing  the  salt  with  a  comparatively  large  amount 
of  butter,  less  working  is  necessary.  Much  of  the  butter  is 
mixed  in  the  churn  without  going  through  the  workers,  and  con- 
sequently less  moisture  will  be  expressed  from  the  butter.  With 
the  same  number  of  revolutions  of  the  churn  the  butter  from 
the  small  churning  is  worked  correspondingly  more  than  the 
butter  from  a  larger  churning.  Medium  firm  butter,  to  a  certain 
limit,  loses  about  .2  per  cent  of  moisture  for  every  revolution  that 
it  is  overworked  in  the  absence  of  water. 

Degree  of  Ripeness. — The  riper  the  cream  is,  all  other  con- 
ditions being  the  same,  the  easier  it  will  churn.  Sweet  cream 
is  viscous,  and  consequently  the  fat-globules  will  not  unite  as 
readily.  The  acid  developed  in  the  cream  seems  to  cut  or  reduce 
the  viscosity  of  the  cream,  although  it  causes  it  to  become  thicker 
in  its  consistency.  Cream  in  an  advanced  stage  of  ripening  is 
brittle,  so  to  speak;  that  is,  if  a  sample  of  the  properly  soured 
cream  is  poured  from  a  dipper  it  will  not  string  but  break  off  in 
lumps. 

If  very  thin  cream  is  overripened,  the  curd  is  coagulated. 
When  this  thickly  coagulated  cream  is  churned,  the  solid  curd 
breaks  up  into  small  curdy  lumps.  These  small  lumps  of  curd 
are  likely  to  incorporate  themselves  in  the  body  of  the  butter 
and  injure  its  quality,  and  also  its  keeping  quality.  If  thin 
cream  has  been  overripened,  it  should  be  strained  well,  and 
care  should  be  taken  not  to  churn  it  to  such  a  degree  as  to 
unite  the  granules  into  lumps  before  the  churn  is  stopped.  If 
the  churn  is  stopped  while  the  butter  is  in  a  granular  form,  the 
most  of  these  curdy  specks  can  be  separated  from  the  butter 
by  copious  washing.     Some  specks  are  likely  to  remain  in  the 


CONDITIONS    AFFECTING   THE    CHURNABILITY    OF    CREAM     249 

butter  when  the  cream  is  in  such  a  condition,  but  by  following 
the  plan  outlined  enough  of  the  specks  can  be  removed  from  the 
butter  so  that  its  commercial  quality  will  not  be  injured.  -The 
degree  of  ripeness  of  cream  does  not  have  any  effect  upon  the 
composition  of  the  butter,  except  in  increasing  the  curd  content  as 
mentioned. 

Nature  of  Agitation. — The  nature  and  degree  of  agitation  of 
cream  affect  the  churnability  considerably.  Many  different 
kinds  of  churns  are  on  the  market  at  the  present  time.  The 
rotary  drum-churns,  now  used  almost  universally  in  this  country, 
are  claimed  to  give  the  greatest  degree  of  agitation;  that  is, 
providing  the  churn  revolves  at  a  proper  rate  of  speed.  If 
the  speed  is  so  great  as  to  cause  the  cream  to  be  influenced  by 
the  centrifugal  force  generated,  rotating  it  with  the  churn,  then 
no  agitation  will  take  place.  Consequently  the  churning 
process  will  be  delayed,  if  not  entirely  prevented.  If  the 
speed  of  the  churn  is  too  slow,  the  degree  of  agitation  of  the 
cream  will  not  be  at  its  maximum,  as  the  cream  will  tend  to 
remain  at  the  lowest  portion  of  the  churn  without  being  agitated. 

In  the  old-fashioned  dash-churn  the  cream  was  not  exposed 
to  much  agitation.  In  Europe  the  upright  barrel-churn  with 
rotary  stirrers  inside  is  mostly  used.  It  is  slower  than  American 
churns,  but  gives  good  satisfaction. 

Extensive  investigational  work  conducted  by  the  American 
Association  of  Creamery  Butter  Manufacturers,  under  the 
direction  of  one  of  the  authors,  has  shown  that  there  are 
several  factors  which  have  a  direct  bearing  upon  the  exhaustive- 
ness  of  the  churning  of  cream.  With  very  sour  cream  that 
has  been  pasteurized,  the  loss  of  fat  in  buttermilk  is  much 
larger  than  is  generally  recognized  by  buttermakers.  The 
average  loss  of  fat  in  buttermilk,  according  to  hundreds  of 
analyses  made  by  the  American  Association  of  Creamery 
Butter  Manufacturers,  is  more  than  five-tenths  of  one  per  cent. 

The  loss  of  fat  in  buttermilk  varies  somewhat  with  the 
seasons  of  the  year.  During  the  hot  weather  in  the  summer 
months,  especially  in  the  flush,  the  loss  of  fat  in  buttermilk 
is  greater  than  in  the  fall  and  winter  months.     One  creamery 


250  CHURNING  AND   WASHING   BUTTER 

that  makes  a  practice  of  testing  its  buttermilk  daily  reported 
to  us  that  for  the  months  of  June  and  July  their  average  loss  was 
.85  per  cent,  some  samples  running  as  high  as  1.25  per  cent. 
Their  tests  were  made  by  the  Mojonnier  method.  So  there 
is  no  question  concerning  the  accuracy  of  the  results  obtained. 

The  high  per  cent  of  fat  found  in  buttermilk  during  the 
period  when  cream  is  very  sour  is  no  doubt  caused  by  the 
high  acid  coagulating  a  portion  of  the  casein  into  small  hard 
lumps,  which  are  not  entirely  broken  up  by  the  process  of 
neutralization  or  churning. 

Another  thing  that  will  affect  the  loss  at  this  period  is, 
the  amount  of  cream  received  is  very  large;  buttermakers  are 
crowded  with  work,  churns  are  filled  too  full,  and  cream  is  not 
held  for  a  long  enough  period  at  churning  temperature  to 
thoroughly  chill  the  fat.  The  result  is  that  the  large  globules 
unite  quickly  in  the  process  of  churning,  due  to  the  soft  condi- 
tion of  the  fat,  and  the  smaller  fat  globules  are  carried  off  in 
the  meshes  of  the  casein  into  the  buttermilk.  It  may  be 
possible  that  the  high  acid  in  the  cream  partly  removes  the 
film  from  the  larger  fat  globules,  and  in  the  process  of  churning 
they  break  up  into  smaller  particles  of  fat.  We  have  no 
positive  knowledge  that  this  is  the  case. 

In  the  investigation  pursued  by  the  American  Association 
of  Creamery  Butter  Manufacturers  it  was  found  that  where 
the  churn  is  filled  about  one-third  full  and  the  cream  is  held 
for  several  hours,  or  overnight,  at  churning  temperature  a 
more  exhaustive  churning  is  obtained  than  where  cream  is  placed 
in  the  churn  immediately  after  being  cooled.  Where  the  lack 
of  churn  or  vat  space  compels  quick  churning  of  the  cream, 
it  is  better  to  cool  the  cream  down  four  or  five  degrees  below 
the  normal  churning  temperature.  The  temperature  that 
cream  can  be  churned  at  will  depend  upon  the  per  cent  of  fat 
in  the  cream.  Cream  that  contains  from  thirty  to  thirty-five 
per  cent  fat  can  be  churned  at  a  very  low  temperature,  especially 
cream  that  contains  a  high  per  cent  of  acid. 

The  speed  of  the  churn  has  also  a  direct  bearing  on  the 
temperature  at  which  cream  can  be  churned,  and  also  a  bearing 


CONDITIONS    AFFECTING    THE    CHURN  ABILITY    OF    CREAM     251 


on  the  loss  of  fat  in  the  buttermilk.  The  speed  of 'the  churn 
will  depend,  to  some  extent,  upon  the  diameter  of  the  churn 
and  the  kind  of  churn  used.  We  find  the  following/  speeds  -give 
very  satisfactory  results:  \ 

Simplex  churn,  24  revolutions  per  minute.  \ 

Disbrow,  Victor,  Dual  and  Perfection  churns,  from  32  to 
35  revolutions  per  minute. 

Where  a  churn  is  run  at  a  low  speed,  the  temperature  of 
the  cream  will  have  to  be  higher  to  cause  the  fat  globules  to 
unite,  due  to  the  lack  of  sufficient  agitation. 

From  microscopical  examination  made  of  buttermilk,  where 
the  loss  was  high,  it  was  found  that  the  fat  seemed  to  be  lodged 
in  the  meshes  of  the  casein.  When  placing  buttermilk  in  bottles 
in  the  laboratory  and  permitting  it  to  stand  overnight,  and 
taking  samples  from  the  upper  or  watery  portion,  the  test  of 
fat  in  this  liquid  portion  was  very  low,  while  in  the  lower  por- 
tion, which  contained  the  casein,  the  per  cent  of  fat  was 
exceedingly  high. 

The  following  tests  of  the  upper  and  lower  portions  of  twelve 
samples  of  buttermilk  from  different  churnings  were  made  after 
allowing  the  samples  to  stand  in  half  pint  bottles  overnight. 
About  half  the  liquid,  or  the  upper  portion  of  the  buttermilk, 
was  decanted  from  the  bottle  in  each  instance,  and  a  comparison 
of  its  test  was  made  with  that  of  the  lower  portion. 


Number 

Test  of  upper 

Test  of 

of  sample 

liquid  portion 

lower  portion 

1 

.48 

1.07 

2 

20 

50 

3 

20 

50 

4 

18 

56 

5 

38 

60 

6 

02 

1 

06 

7 

30 

39 

8 

14 

38 

9 

18 

44 

10 

14 

57 

11 

18 

74 

12 

11 

58 

252  CHURNING  AND  WASHING  BUTTER 

Cream  that  is  separated  from  sweet  milk  at  the  creamery 
can  be  ripened  or  soured  to  a  fairly  high  degree  of  acidity 
without  having  the  lumpy  condition  referred  to  above,  and 
a  very  exhaustive  churning  can  be  had  from  the  same, 
whether  pasteurized  or  unpasteurized.  Where  various  lots 
of  sour  cream  are  received  at  the  creamery,  the  average  per 
cent  of  acidity  of  the  entire  lot  when  mixed  together  may 
not  be  very  high,  but  some  portions  of  this  cream  possibly  have 
contained  an  acidity  of  well  over  i  per  cent;  hence,  the 
loss  of  fat  in  such  cream  would  be  greater  than  if  the  cream 
had  been  separated  from  sweet  milk  and  where  the  souring 
was  under  the  control  of  the  maker.  To  get  an  exhaustive 
churning  with  sour  cream,  the  same  should  have  the  'acidity 
reduced  to  a  low  degree.  Partial  neutralization  has  the 
effect  of  putting  the  casein  in  a  more  flocculent  condition; 
hence,  the  loss  is  not  as  great. 

Neutralization  should  always  be  done  before  pasteuriza- 
tion, as  otherwise  the  heat  of  pasteurization  will  precipi- 
tate some  of  the  casein  into  hard  lumps,  which  will  not 
be  broken  by  the  agitation  of  the  churn  in  the  process  of 
churning. 

As  far  as  the  working  of  butter  goes,  any  of  the  modern 
churns  will  do  efficient  work,  especially  when  the  maker  has 
got  himself  accustomed  to  the  churn  he  is  operating. 

Size  of  Fat-globules. — Cream  containing  large  fat-globules 
churns  more  quickly  than  cream  containing  small  globules  and  a 
more  exhaustive  churning  can  also  be  obtained  from  it.  It  is, 
however,  impossible  to  obtain  cream  which  does  not  contain  any 
of  the  small  globules.  The  minute  globules  are  always  difficult 
to  remove  from  the  serum,  whether  it  be  in  the  churning  or  in 
the  separation.  In  the  churning  there  is  a  certain  force  which 
always  tends  to  hold  the  globules  in  place.  This  force  acts  in  a 
correspondingly  greater  degree  upon  the  small  globules.  They 
are  held  in  position  and  move  only  when  the  cream  is  exposed  to 
agitation.  Cream  containing  larger  globules  allows  them  to 
escape  from  their  position  with  greater  ease  than  does  cream 
containing  the  minute  globules.     The  globules  which  are  not 


COLOR  253 

removed  from  the  buttermilk  during  the  churning  process  are 
largely  of  the  small  type. 

Straining  of  Cream. — Before  the  cream  is  transferred  from 
the  ripening-vat  to  the  churn  it  should  be  strained  through  a 
fine  perforated  tin  strainer.  This  can  be  conveniently  done 
during  the  changing  of  the  cream  from  the  ripening- vat  to  the 
churn.  Special  strainers  are  now  manufactured  which  can 
be  hooked  onto  the  churn,  and  the  cream  can  run  directly  from 
the  ripening-vat  through  the  strainer  into  the  churn.  This 
straining  of  the  cream  separates  all  the  lumps  which  cire  likely 
to  appear.  It  also  separates  any  other  coarse  impurities  which 
may  be  present.  If  these  impurities  were  not  separated  they 
would  probably  be  embodied  in  the  butter  and  cause  an  unsightly 


Fig.  95. — Cream  and  milk  strainer. 

appearance.  They  would  also  be  likely  to  injure  the  keeping 
quality  of  the  butter,  but  this  would  depend,  of  course,  upon 
the  character  of  the  impurities. 

Color. — In  order  to  maintain  a  uniform  color  in  the  butter 
during  the  different  seasons,  it  is  essential  that  some  artificial 
color  be  added  at  certain  times.  During  the  latter  part  of 
May  and  the  early  part  of  June  the  butter  has  a  rich  yellow 
color,  which  is  accepted  as  the  standard  color  of  butter.  This 
is  often  referred  to  as  the  u  June  color." 

There  are  several  different  butter-colors  on  the  market,  for 
which  special  merits  are  claimed.  All  the  colors,  so  far  as  known, 
are  efficient  in  imparting  color  to  the  butter  without  materially 
coloring  the  buttermilk.  A  good  butter-color  should  be  a  sub- 
stance which  does  not  impart  a  bad  smell  or  taste  to  the  butter. 
It  should  possess  strong  coloring  properties,  so  that  very  little 


254  CHURNING  AND   WASHING   BUTTER 

of  it  would  have  to  be  added  in  order  to  impart  the  desirable 
color.  It  should  not  be  injurious  to  health.  Some  colors  are 
prepared  from  the  fruit  of  the  annato  tree,  which  grows  in  the 
East  Indies  and  South  America.  The  coloring  matter  on  the 
inner  part  of  the  covering  of  this  fruit  is  dissolved  in  a  suitable 
oil,  such  as  sesame  or  hemp. 

Before  any  of  the  proper  commercial  butter-colors  were  put 
upon  the  market,  extracts  of  carrots,  marigold,  saffron,  and 
annato  were  used.  The  yolk  of  eggs  has  also  been  used  to 
some  extent.  It  is  said  that  carrot-juice  is  the  most  healthful 
butter-color. 

The  amount  of  color  to  add  depends  upon  the  market  require- 
ments, and  upon  the  season  of  the  year.  As  was  mentioned 
before,  in  June  little  or  no  color  should  be  added.  As  the  summer 
season  advances  the  amount  of  color  added  can  be  gradually 
increased.  During  winter,  while  the  cows  are  on  dry  feed, 
the  maximum  amount  of  color  is  generally  used.  Color  require- 
ments of  the  butter  vary  considerably  at  the  same  season  of  the 
year.  American  markets  demand  a  higher  color  than  European 
markets.  The  northern  markets  desire  a  light  straw  color, 
while  the  southern  markets  want  a  deeper  color,  almost  an 
orange  color.  The  Jewish  trade  requires  uncolored  butter. 
In  some  of  the  European  countries  no  color  is  used.  The 
English  market,  which  is  the  greatest  butter  market  in  the  world, 
demands  butter  that  has  a  very  light  straw  color.  The  main 
object  in  coloring  butter  is  to  maintain  a  uniform  color  during 
the  different  seasons  of  the  year.  The  amount  of  color  to  add 
during  the  different  seasons  will  usually  vary  between  none  and  a 
trifle  over  2  ounces  for  every  100  pounds  of  fat. 

The  color  should  be  added  to  the  cream  before  the  churn 
has  been  started.  If  this  has  not  been  done,  the  butter  can  be 
colored  by  mixing  the  color  with  the  salt.  The  salt  should 
then  be  well  distributed  and  worked  into  the  butter  until  the 
body  of  the  butter  assumes  a  uniform  color.  The  chief  objec- 
tion to  this  method  is,  that  it  is  difficult  to  work  in  the  color 
thoroughly  without  injuring  the  butter. 

The  sole  object  in  adding  color  is  to  give  the  butter  a  more 


WHEN  TO  STOP  THE  CHURNING  255 

attractive  appearance.  It  neither  adds  to  nor  takes  from  the 
flavor  or  food  value  of  butter.  Hence  the  shade  of  color  should 
be  such  as  will  make  the  butter  most  attractive  in  appearance. 
This  varies  somewhat  with  the  market  to  which  the  butter  is 
going. 

When  to  Stop  the  Churning. — Different  makers  have  various 
ways  of  ascertaining  when  the  churning  process  has  been  com- 
pleted. Some  determine  the  proper  churning  stage  by  the  size 
of  granules,  others  by  the  height  at  which  the  butter  floats  in 
the  buttermilk.  Others  again  depend  upon  the  appearance  of 
the  buttermilk.  It  is  well  to  let  all  of  these  factors  influence 
the  operator  in  deciding  when  the  churn  should  be  stopped,  as  no 
one  of  them  may  be  a  sufficient  indication. 

The  size  of  the  granules  is  the  most  common  factor  that 
determines  the  time  when  the  churn  should  be  stopped.  It 
has  been  a  general  rule  in  the  past  to  stop  the  churning  when 
the  granules  are  a  little  larger  than  wheat-kernels.  As  a  rule 
it  is  safer  to  carry  the  churning  on  a  little  further  until  the 
granules  increase  to  the  size  of  corn-kernels,  irregular  and  flaky 
in  shape.  At  this  stage  the  buttermilk  will  usually  appear 
bluish  in  color,  and  the  butter  is  raised  above  the  buttermilk 
a  considerable  distance.  When  the  butter  is  churned  to  too 
small  granules,  many  of  them  will  go  through  the  strainer  into 
the  buttermilk,  and  cause  a  considerable  loss.  When  butter 
in  such  shape  is  washed  in  medium-cold  wash- water,  the  granules 
continue  to  remain  in  a  separate  state.  When  salt  is  added, 
the  moisture  is  extracted  from  them,  and  the  water  is  likely  to  be 
caught  in  holes  and  crevices  during  the  working  and  cause  leaky 
butter.  If  the  churning  is  carried  on  a  little  further,  the  granules 
will  not  escape  into. the  buttermilk,  the  churning  will  be  more 
complete,  and  the  moisture  will  be  incorporated  in  a  better  con- 
dition. 

Overchurning  should  be  avoided  as  much  as  underchurning. 
If  butter  is  overchurned  in  the  buttermilk,  it  will  retain  a  large 
amount  of  the  buttermilk,  which  will  be  very  difficult  to  remove 
by  washing.  Overchurning  butter,  especially  at  a  medium- 
high  temperature,  is  very  effective  in  increasing  the  moisture- 


256  CHURNING  AND  WASHING  BUTTER 

content  of  butter,  and  should  be  guarded  against  for  that  reason. 
Butter  containing  more  than  16  per  cent  water  is  not  permissible 
on  the  American  market. 

When  cream  is  in  a  poor  condition  it  should  not  be  over- 
churned,  as  the  incorporation  of  buttermilk  produces  a  very 
rank  and  unclean  flavor  in  the  butter.  Cream  in  such  condi- 
tion also  contains  many  undesirable  germs,  which,  when  incor- 


jj 

J  * 

* 

Fig.  96. — Butter  from  1  pound  of  fat  in  cylinders,  showing  the  effect  of  differ- 
ent percentages  of  water  upon  quantity.  The  water-content  of  these  samples 
ranges  between  8  per  cent  and  19  per  cent, 

porated  into  the  butter,  will  cause  it  to  deteriorate  to  a  great 
extent.  When  the  cream  is  in  poor  condition,  the  churn  should 
be  stopped  as  early  as  is  consistent  with  the  completeness  of 
churning.  The  buttermilk  should  be  removed  and  the  butter 
washed  thoroughly  in  clean,  pure  wash-water.  If  the  wash- 
water  is  added  while  the  butter  is  in  this  granular  condition,  the 
buttermilk  can  be  very  effectively  removed.  If  one  washing  is 
not  sufficient,  wash  three  or  four  times.     In  such  a  case  the  tern- 


CONDITION  OF  WATER  IN  BUTTER 


257 


Fig.  97. — Butter  sample, 
15.61  per  cent  water. 


Or)  ■    fy\  #  , 
:*■  ;       •  •  , 


Fig.  98. — Butter  sample, 
15.31  per  cent  water. 


Fig.  99. — Butter  sample,  13.37  per  cent  water;  leaky,  2  per  cent  brine. 

Microscopical  views  showing  condition  dt  water  in  butter.  Fig.  97  shows  that 
the  water  has  been  incorporated  in  the  form  of  very  minute  particles.  Storch 
found  from  nine  million  to  sixteen  million  water  particles  per  cubic  millimeter. 
Such  butter  appears  dry  and  a  little  dull.  Fig.  98  shows  the  water  incor- 
porated in  medium-small  particles.  There  were  on  an  average  three  and  three- 
fifths  millions  of  water  particles  per  cubic  millimeter  in  such  butter.  Fig.  99 
shows  condition  of  water  in  leaky  butter.  Storch  found  about  two  and  one- 
half  million  water  particles  per  cubic  millimeter  in  butter  having  such  a  body. 
(Views  by  Storch.) 


258  CHURNING  AND  WASHING  BUTTER 

perature  should  be  low.  If  the  temperature  of  the  wash-water 
is  high,  and  the  butter  is  washed  excessively,  it  will  contain  too 
much  moisture  when  it  is  finished,  and  is  likely  to  be  salvy. 
If  washed  with  water  at  a  low  temperature  the  butter  will  not 
incorporate  so  much  water.  What  it  does  incorporate  in  excess, 
will,  as  a  rule,  be  expressed  during  the  working  of  the  butter — a 
result  due  to  its  firmness. 

If  the  attempt  is  made  to  incorporate  water  by  working  the 
butter  in  water  after  the  salt  has  been  added,  while  the  butter  is 
in  a  hard,  granular  condition,  it  will  usually  appear  leaky. 

If  cream  is  in  a  good  condition,  overchurning  to  a  small  extent 
does  not  produce  any  bad  results.  The  germs  which  are  present 
in  pure  and  well-ripened  cream  are  not  deleterious  to  the  keeping 
quality  of  the  butter.  The  amount  of  butter-milk  incorporated 
in  the  butter  is  not  sufficient  to  cause  any  bad  effects  upon  its 
quality.  If  the  cream  is  in  proper  condition  it  is  difficult  to 
incorporate  any  more  than  3  per  cent  of  curd  into  the  butter. 
While  overchurning  is  not  to  be  recommended,  if  it  is  at  any  time 
desirable,  it  should  be  done  in  the  washwater  rather  than  in  the 
buttermilk. 

Churning  Mixed,  Sweet,  and  Sour  Cream. — When  two  lots  of 
cream  are  to  be  churned,  one  sweet  and  the  other  sour,  they 
should  be  churned  separately.  If  the  two  lots  of  cream  are 
mixed  together,  the  sour  cream  churns  more  quickly  than  the 
sweet  cream.  As  a  consequence  the  churn  is  likely  to  be 
stopped  before  the  fat  from  the  sweet  cream  has  been  completely 
separated  from  the  serum. 

At  some  of  the  creameries  conditions  are  such  that  the  oper- 
ator may  be  tempted  to  mix  the  two  lots  of  cream.  Where 
sweet  cream  arrives  at  the  creamery  just  previous  to  churning 
time,  it  is  advisable  not  to  mix  the  sweet  cream  with  the  sour. 
It  is,  as  a  rule,  better  to  carry  the  sweet  cream  over  to  the  next 
churning,  or,  if  necessary,  churn  it  separately. 

Difficult  Churning. — Difficult  churnings  in  creameries  are 
not  very  common.  In  farm  butter-making  they  are  more  fre- 
quent, especially  in  the  fall.  At  this  time  the  cows  are  usually 
well  advanced  in  the  period  of  lactation,  and  early  in  the  winter 


DIFFICULT  CHURNING  259 

they  are  often  fed  on  food  which  causes  hard  butter  fat,  as 
described  under  "  Effect  of  Food  upon  Fat."  In  the  fall  or 
early  winter,  a  large  portion  of  the  milk  is  usually  obtained 
from  strippers,  or  cows  almost  dried  up.  Such  milk  contains  a 
large  portion  of  the  small  fat-globules.  Difficult  churning 
resulting  from  such  conditions  can  usually  be  remedied  by  ripen- 
ing to  a  higher  degree  of  acidity  and  churning  the  cream  at  a 
higher  temperature. 

Complaints  are  occasionally  heard  of  difficult  churning  which 
cannot  be  remedied  by  such  treatment.  Sometimes  cream  froths, 
and  will  not  agitate  in  the  churn.  Such  a  frothy  condition  has 
in  some  cases  been  found  to  occur  even  though  the  cream  may 
seem  to  be  in  an  ideal  condition  for  churning.  It  is  believed 
by  some,  notably  Hertz,  that  such  a  condition  in  the  cream  is 
brought  about  by  a  disease  of  the  cow.  Weigman  has  studied 
and  isolated  a  ferment  which  caused  a  soapy  condition  of  milk 
and  cream.  It  is  possible  that  such  exceedingly  difficult  cases 
in  churning  may  be  due  to  a  disease  of  the  cow,  and  it  may  also 
be  due  to  certain  ferments  that  produce  a  soapy  condition  of  the 
cream. 

If  thick  cream  at  a  very  low  temperature  is  put  into  the 
churn,  it  sometimes  causes  difficult  churning.  When  such 
cream  is  first  agitated  in  the  churn  it  incorporates  considerable 
air.  This  air,  together  with  the  various  gases  developed  at  a 
low  temperature,  does  not  readily  escape.  The  viscosity  of  it  is 
so  great  that  it  will  not  release  the  air  present.  As  a  conse- 
quence it  assumes  a  stiff  consistency,  much  the  same  as  the  beaten 
white  of  an  egg.  If  cream  froths  in  the  churn  as  mentioned, 
a  little  warm  water  thrown  on  the  outside  of  the  churn  will 
often  start  the  agitation  of  the  cream  within.  If  a  combined 
churn  is  used  the  rollers  may  be  put  in  gear,  and  the  churn 
revolved  in  slow  gear.  This  will  often  start  the  cream  to  agitate. 
If  these  two  remedies  are  not  sufficient,  a  little  water,  lukewarm  if 
necessary,  may  be  added  directly  to  the  cream.  By  letting 
the  churn  stand  a  short  time,  the  cream  will  usually  condense 
into  a  liquid  form  again,  and  many  times  the  churning  process 
can  then  be  completed.     This  latter  method,  however,  usually 


260  CHURNING  AND   WASHING  BUTTER 

requires  more  time  than  can  be  profitably  spared.     If  the  churn- 
ing difficulty  is  of  a  serious  nature  the  remedies  are : 

(i)  If  produced  by  a  certain  cow,  or  herd,  find  out  whether 
it  is  produced  by  a  fermentative  process,  or  by  other  abnormal 
conditions  of  the  cow. 

(2)  Change  the  food  of  the  cow.  A  succulent  food  will 
usually  cause  the  cow  to  secrete  more  milk,  and  of  a  different 
nature. 

(3)  If  produced  by  a  ferment,  endeavor  to  control  the  fer- 
mentation as  previously  described. 

(4)  Ripen  the  cream  to  a  higher  degree  of  acidity. 

(5)  Skim  thicker  cream  and  churn  at  a  higher  temperature. 
The  last  three  methods  will  cure  most  cases  of  diificult 

churnings. 

Keeping  Churn  Sweet. — It  has  been  mentioned  before  that 
butter  absorbs  foreign  odors  very  readily.  If  the  churn  is  not 
kept  in  a  pure,  sweet  condition,  the  butter  will  be  exposed  to  the 
undesirable  odors  and  its  commercial  quality  will  be  impaired. 
The  best  butter  cannot  be  produced  in  a  foul-smelling  churn. 
As  churns  often  are  not  used  every  day,  they  very  readily  assume 
this  impure  condition,  and  it  is  essential  that  special  care  be 
taken  in  keeping  them  clean. 

The  best  method  of  keeping  churns  in  good  condition  is  to 
rinse  the  churn  in  two  waters  at  the  end  of  each  churning. 
The  first  rinsing  should  be  made  with  lukewarm  water,  the 
second  with  scalding  hot  water.  Some  prefer  to  turn  the 
churn  over  with  mouth  down.  Others  prefer  to  allow  the  cover- 
hole  to  turn  up.  When  the  churn  is  turned  with  the  cover- 
hole  down,  the  remaining  steam  on  the  inside  of  the  churn  will 
not  escape.  It  will  condense  inside  of  the  churn,  and  cause  the 
churn  to  remain  in  a  damp  condition  overnight  or  even  longer. 
If  the  churn  is  turned  with  the  cover-hole  up  the  dust  and  other 
impurities,  if  present,  are  likely  to  settle  into  the  churn.  A  good 
way  is  to  turn  the  churn  over  so  that  the  cover-hole  points  to 
one  side.  The  churn  should  be  thoroughly  drained  first,  other- 
wise some  water  will  remain  in  the  bottom.  When  the  churn 
is  left  with  the  cover-hole  at  one  side,  the  steam  can  escape, 


KEEPING   CHURN  SWEET  261 

and  the  heat  absorbed  from  the  wash-water  will  dry  the  churn 
thoroughly.  Many  makers  rinse  the  churn  only  once  and  use 
scalding  hot  water.  This  method  is  likely  to  scald  the  remaining 
curd  on  to  the  wood;  secondly,  one  rinsing  is  not  enough  to 
insure  a  clean  churn.  The  first  rinsing  with  lukewarm  water 
removes  the  major  portion  of  the  buttermilk  and  brine,  and  to  a 
certain  extent  warms  the  wood  of  the  churn,  so  that  when  the 
second  rinsing  with  scalding  hot  water  is  completed,  the  churn 
has  been  thoroughly  scalded.  In  addition,  the  churn  is  clean, 
and  no  food  is  left  on  which  germs  can  thrive.  The  churn  is 
also  left  warm,  and  in  that  condition  will  dry  quickly. 

Some  makers  prefer  to  keep  the  churn  in  a  good  condition  by 
sprinkling  salt  on  the  inside  after  washing.  This  is  not  to  be 
recommended,  as  all  churns  contain  more  or  less  iron- ware  on 
the  inside.  Salt,  while  a  fair  germicide,  causes  the  formation 
of  rust  on  all  iron  with  which  it  comes  in  contact.  After  a  time 
this  rust  will  scale  off  to  a  certain  extent  and  become  incorporated 
with  the  butter. 

If  the  churn  is  treated  daily  in  the  manner  described  above 
and  then  at  the  end  of  the  week  treated  with  slaked  lime, 
it  can  be  kept  in  a  good  sweet  condition.  The  lime  should 
be  freshly  slaked  and  in  a  liquid  condition  when  put  in  the  churn. 
A  pailful  or  two  of  this  fluid  will  be  sufficient  for  each  churn. 
By  rotating  the  churn  a  few  times  the  lime  will  be  spread  all 
over  the  inside  of  it.  Let  the  churn  remain  in  this  con- 
dition until  ready  for  use  again.  When  ready  for  use,  put  in 
'some  warm  water,  and  the  lime  will  readily  come  off.  But  if 
it  has  been  allowed  to  remain  in  the  churn  too  long,  it  will  form  a 
lime  carbonate,  and  will  be  more  difficult  to  remove. 

Lime  is  one  of  the  best  disinfectants  and  deodorizers  that  can 
be  used  in  a  creamery.  Some  of  the  best  butter-makers  use  it 
every  day  on  all  the  wooden  utensils,  such  as  butter-workers, 
churns,  etc.  Lime  can  be  used  more  advantageously  in  Amer- 
ican creameries  than  it  is  to-day.  Many  creameries  would  be  in 
a  much  sweeter  and  purer  condition  if  they  were  given  a  good 
coat  of  whitewash  on  the  inside  once  a  month.  Refrigerators, 
wooden  utensils,  and  rooms  of  any  kind  can  be  kept  in  a  good, 


262  CHURNING  AND  WASHING  BUTTER 

sweet  and  pure  condition  by  whitewashing  or  sprinkling  a  little 
lime  on  them. 

In  the  preparation  of  a  new  churn  for  use  it  is  a  good  plan 
to  treat  it  with  milk  of  lime  in  the  manner  already  described. 
It  will  fill  the  pores  of  the  wood  and  harden  it,  and  remove  all 
danger  of  imparting  a  woody  flavor  to  the  butter  of  the  first 
churnings  made  in  the  churn. 

To  Prevent  Butter  from  "  Sticking  "  to  the  Churn. — At  times 
churns  get  into  a  condition  in  which  butter  sticks  or  adheres  to 
them  more  or  less.  Sometimes  it  requires  treatment  with  a  weak 
acid  solution  to  overcome  this  difficulty,  and  sometimes  treatment 
with  an  alkali  solution  is  needed.  If  treatment  with  acid  is 
what  is  needed,  a  weak  solution  of  either  sulphuric  or  muriatic 
acid  may  be  used — say  a  pint  to  ioo  gallons  of  water.  The 
acid  must  be  added  carefully  to  the  water  in  the  churn  and 
none  of  it  must  be  poured  directly  upon  the  wood.  The  churn 
is  revolved  with  this  solution  in  it,  for  about  five  minutes  at  a 
time,  at  intervals  extending  over  a  period  of  several  hours. 
It  is  then  rinsed  with  warm  water  and  then  with  water  containing 
a  little  of  some  good  washing  powder,  such  as  Wyandotte. 
If  treatment  with  an  alkali  solution  is  needed,  which  is  the  case 
if  fat  has  soaked  into  the  wood,  a  suitable  washing  powder  may  be 
used  to  remove  the  difficulty.  The  following  is  an  extract  from 
a  letter  received  from  one  of  our  leading  creameries  which  had 
written  for  and  received  suggestions  from  one  of  the  authors  for 
overcoming  this  difficulty:  "  We  received  your  letter  in  regard  to 
the  trouble  we  had  with  the  butter  sticking  to  our  churn.  We 
are  pleased  to  advise  that  we  have  apparently  eliminated  all 
of  this  condition.  When  we  received  your  letter  suggesting 
remedies  which  might  stop  this  condition,  we  at  first  used  the 
muriatic  acid  but  without  any  results  whatever.  Then  our 
butter-maker  took  about  three  pails  of  Wyandotte,  put  in  a  small 
amount  of  water  and  heated  with  steam  until  he  made  a  sort  of  a 
paste  out  of  it.  He  then  put  it  in  the  churn  and  gave  it  several 
revolutions  and  let  it  stand  overnight,  then  washed  it  out 
thoroughly  with  hot  water.  The  first  time  it  seemed  to  help 
it  very  considerably,  so  we  gave  it  another  dose  a  day  or  two 


WASHING  OF  BUTTER  263 

later  and  it  has  relieved  the  whole  condition.  He  is  of  the 
opinion  that  if  this  is  used  when  the  butter  shows  any  ten- 
dency to  stick  to  the  churn,  it  will  keep  the  churn  in  good  con- 
dition right  along. " 

WASHING  OF  BUTTER 

Purpose  of  Washing.  The  chief  object  of  washing  butter 
is  to  remove  as  much  buttermilk  as  possible.  The  more  impure 
the  cream  is,  the  greater  is  the  importance  of  getting  the  butter 
thoroughly  washed.  In  the  winter,  when  it  is  cold,  and  the 
cream  is  in  good  condition,  some  makers  do  not  wash  the  butter 
at  all.  But  this  is  not  a  safe  method.  The  removal  of  the 
buttermilk  constituents  should  be  as  complete  as  conditions  will 
permit. 

Temperature  of  Wash-water. — The  temperature  of  wash- 
water  should  be  as  nearly  like  that  of  the  cream  when  churned 
as  is  consistent  with  the  other  conditions.  It  is  quite  a  regular 
practice  in  many  creameries,  particularly  in  summer,  to  temper 
the  wash-water  to  about  2°  below  the  churning  temperature  of 
the  cream.  Extreme  and  rapid  changes  in  temperature  should 
always  be  avoided.  Occasionally  it  is  necessary  to  use  water 
that  is  colder  than  the  cream;  at  other  times  it  is  necessary  to 
use  wash- water  at  a  higher  temperature  than  that  of  the  cream. 
If  the  butter  churns  soft,  do  not  use  ice-cold  wash-water  to  chill 
the  butter,  as  it  has  a  tendency  to  give  butter  a  tallowy  appear- 
ance. Neither  should  hard  butter  be  quickly  softened  by  using 
wash- water  at  u  very  high  temperature,  as  it  is  likely  to  cause  the 
butter  to  assume  a  greasy  and  slushy  texture.  If  it  is  necessary 
to  change  the  degree  of  hardness  of  the  butter,  change  it  grad- 
ually by  using  water  at  a  moderate  temperature  and  allowing  the 
butter  to  be  in  contact  with  it  a  longer  time  without  agitating 
it  much. 

The  regulation  of  the  condition  or  degree  of  firmness  of  butter, 
for  the  proper  working  of  it,  should  never  have  to  be  accom- 
plished to  any  great  extent  by  means  of  the  wash-water.  This 
is  not  the  real  purpose  of  washing  butter.     If  the  churning  tern- 


264  CHURNING  AND  WASHING  BUTTER 

perature  of  the  cream  be  right,  the  butter  will  be  in  proper  con- 
dition for  washing  and  working.  If  the  churning  temperature 
be  not  right  it  is  difficult  through  any  device  that  may  be 
adopted  subsequently — such  as  tempering  the  wash-water — to 
bring  the  butter  into  the  best  condition  for  salting  and  working. 
Regulation  by  means  of  a  change  in  temperature  of  the  wash- 
water  will  prove  a  partial,  but  not  a  complete  remedy — par- 
ticularly if  the  butter  be  very  soft  when  it  comes. 

Unless  the  butter  is  of  very  poor  quality,  excessive  washing 
should  be  avoided.  Cold  water  is  said  to  absorb  a  considerable 
portion  of  the  flavoring  substances.  If  the  quality  of  the  butter 
is  poor,  many  of  the  undesirable  flavors  and  odors  are  removed 
by  excessive  washing;  while  if  the  butter  has  a  fine,  rich  flavor, 
it  should  be  retained,  and  not  extracted  by  washing  the  butter 
more  than  is  needed.  No  definite  temperature  can  be  given,  as 
the  temperature  of  wash- water  must  vary  according  to  the  hard- 
ness of  the  butter  when  churned. 

If  the  temperature  of  the  wash-water  is  too  high,  and  the 
churning  in  the  wash- water  is  continued  a  very  long  time,  much 
water  will  be  incorporated  in  the  butter.  If  the  butter  is  quite 
firm  in  the  first  place,  and  the  temperature  of  the  wash- water 
is  not  above  6o°  F.,  there  is  not  much  danger  of  getting  too 
much  water  in  the  butter.  Rapid  changes  in  the  degree  of 
hardness  of  the  butter  in  the  presence  of  water  are  conducive  to  a 
high  moisture-content.  Very  soft  butter  chilled  in  very  cold 
water,  and  hard  butter  softened  in  very  warm  wash-water  are 
two  conditions  which  should  be  avoided. 

As  to  the  quantity  of  wash  water  that  should  be  used :  with 
cream  of  average  richness,  it  will  be  about  the  same  as  that  of  the 
buttermilk;  with  very  rich  cream  a  little  greater.  In  washing 
the  butter  the  churn  is  usually  run  from  10  to  15  revolutions  on 
high  speed.  Some,  instead  of  following  this  practice  of  churning 
the  butter  in  the  wash  water,  run  the  churn  about  2  to  5  revolu- 
tions at  slow  speed  with  the  worker  in  gear;  modifications  and 
combinations  of  these  two  methods  are  made.  For  instance, 
where  butter  is  first  washed  or  sprayed  and  a  second  wash-water 
is  used,  some  adopt  the  practice,  during  the  second  washing,  of 


WASHING  OF  BUTTER  265 

revolving  the  churn  a  few  times  on  high  speed  while  others  put 
the  rolls  in  motion  using  the  slow  gear. 

Butter  from  cream  of  good  quality,  churned  at  the  right 
temperature,  needs  less  washing  than  butter  from  cream  of  poor 
quality  or  butter  churned  at  too  high  a  temperature.  Two 
washings  should  suffice  when  the  cream  is  of  good  quality,  and 
with  such  cream  some  wash  the  butter  only  once  if  the  wash- 
water  runs  off  clear.  In  order  to  possess  good  keeping  qualities, 
butter  must  have  the  buttermilk  well  washed  out  of  it.  Butter 
from  cream  of  poor  flavor  requires  more  washing  than  butter 
from  cream  that  is  clean  in  flavor. 

Kind  of  Wash- water  to  Use. — In  the  washing  of  butter,  it  is 
very  essential  that  water  used  should  be  the  best  obtainable. 
The  creamery  water-supply  is  evidently  much  better  now  than 
it  was  years  ago.  Pond- wells  and  shallow  wells  are  gradually 
passing  out  of  existence,  but  there  are  yet  many  shallow  wells 
from  which  water  is  drawn  for  creamery  purposes.  Water  from 
wells  may  appear  to  be  pure,  and  yet  contain  germs  which  are 
deleterious  to  dairy  products,  and  especially  to  the  keeping  qual- 
ity of  butter.  That  water  of  average  purity  contains  such  germs 
has  been  demonstrated  in  this  country,  as  well  as  in  foreign 
countries.  Shallow  well  water  contains  on  an  average  about 
15,000  germs  per  cubic  centimeter,  but  Miquel  has  found  that  a 
rapid  power  of  multiplication  characterizes  the  bacteria  in  pure 
spring-water,  while  in  impure  water  the  multiplication  is  slower. 
Water  containing  only  this  number  of  germs  is,  as  a  rule  consid- 
ered very  pure.  Most  creameries,  however,  pump  their  water 
into  a  tank  overhead  in  the  creamery,  where  it  is  contaminated 
with  bacteria  and  impurities  of  different  kinds. 

Shallow  wells  are  usually  surrounded  with  conditions  which 
do  not  guarantee  a  creamery  pure  water  during  the  different 
seasons  of  the  year.  In  the  spring,  when  rains  are  frequent  and 
heavy,  unwholesome  surface-water  is  likely  to  seep  in  through 
the  sides.  Such  wells  may  also  serve  as  traps  for  small  animals. 
The  presence  of  an  animal  in  the  well  is  sure  to  cause  undesirable 
odors  and  a  multitude  of  undesirable  and  putrefactive  organisms. 

Water  from  deeply  drilled  wells,  even   if  it  is  pure  in  so  far 


266  CHURNING  AND  WASHING  BUTTER 

as  its  germ-content  is  concerned,  is  in  many  cases  turbid  and 
sandy,  and  needs  to  go  through  a  process  of  purification  as  much 
as  does  the  shallow  well  water. 

METHODS   OF  PURIFYING  WASH-WATER 

There  are  two  practical  and  effective  methods  of  purifying 
wash- water,  viz.,  (i)  Filtration,  and  (2)  Pasteurization.  Which 
of  these  two  methods  is  the  most  practicable  and  the  most 
effective  in  the  creamery  depends  upon  the  conditions  and  upon 
the  quality  of  the  water.  In  the  case  of  water  from  deep  wells, 
which  contains  little  or  no  organic  matter,  but  at  the  same  time 
is  infested  with  undesirable  germs,  pasteurization  is  perhaps 
more  expedient.  Filtration,  if  the  same  degree  of  thoroughness 
is  to  be  reached  as  in  pasteurization,  is  a  comparatively  slow 
process.  Pasteurization  of  wash- water  is  a  trifle  more  expensive 
than  filtration.  Wash-water  can  be  pasteurized  at  the  same 
time  that  the  churning  is  being  done,  thus  economizing  in  time 
and  fuel.  Pasteurization  is  quite  effective  in  rendering  the  water 
germ-free,  but  it  is  not  so  effective  in  removing  any  organic 
matter  or  other  tangible  impurities  which  may  be  present.  If 
the  creamery  does  not  already  have  a  pasteurizer,  filtration  can 
be  employed  very  profitably,  and  under  average  conditions  it 
will  perhaps  give  the  best  results. 

Filtration. — Filtration  is  inexpensive,  and  is  a  very  efficient 
method  of  purifying  wash-water.  It  seems  strange  that  bac- 
teria can  be  removed  from  water  by  passing  through  layers  of 
sand,  gravel,  coke,  and  charcoal,  but  such  is  the  case.  Filtra- 
tion is  applicable  to  all  kinds  of  water;  even  if  the  water  appears 
pure,  it  is  well  to  filter  it.  Fewer  germs  and  fewer  varieties 
of  micro-organisms  are  apparently  found  in  deep  well  water 
than  is  the  case  in  water  from  surface-wells;  hence  the  ferments 
which  are  present  will  have  a  free  field  for  developing  in  the 
absence  of  competing  forms.  If  a  sample  of  water  which  is 
rich  in  micro-organisms  is  violently  shaken  with  a  certain 
amount  of  charcoal,  coke,  chalk  or  similar  substances,  and  then 
left  for  a  time  to  settle,  the  pure  layer  of  water  at  the  top  will  be 


METHODS  OF  PURIFYING  WASH-WATER  267 

almost  entirely  free  from  germs,  and  in  some  cases  entirely 
sterile.  It  used  to  be  thought  by  older  German  investigators 
that  these  different  filtering  substances  had  almost  miraculous 
power  of  removing  organisms  from  water. 

The  factors  which  are  to  be  considered  in  successful  filtration 
are: 

(i)  Storage  capacity  for  until tered  water. 

(2)  Construction  of  filter-beds. 

(3)  Rate  of  filtration. 

(4)  Renewal  of  filter-beds. 

(1)  Concerning  the  storage  capacity,  nearly  all  creameries 
have  storage-tanks  overhead  in  the  creamery;  so  far  as  that  is 
concerned,  however,  filtration  can  be  successfully  carried  on 
continuously  as  well  as  intermittently. 

(2)  The  construction  of  the  filter-bed  used  in  the  experi- 
ment carried  on  at  the  Iowa  Experiment  Station,  Ames,  Iowa, 
is  as  shown  in  Fig.  101.  The  approximate  proportionate  depth 
of  each  layer  in  the  bed  is  as  follows,  beginning  at  the  bottom: 

Two  inches  small  flint  stones;  22  inches  fine  sand;  12  inches 
fine  coke;  9  inches  charcoal;  2  inches  fine  stone  or  coarse  gravel. 
The  layer  of  fine  sand  should  not  be  less  than  1 5  inches.  It  has 
been  asserted  that  a  few  pieces  of  old  iron  mixed  in  the  filter-bed 
are  beneficial.  Alum,  lime,  and  copperas  have  been  recom- 
mended for  clarifying  and  deodorizing  very  impure  water.  As 
these  substances  are  soluble  they  should  not  be  used  in  filter- 
beds,  which  are  intended  for  the  filtration  of  water  for  potable 
purposes.  The  filtering-can  was  made  from  22  galvanized  iron. 
The  height  of  can  is  48  inches;  diameter,  18  inches.  The  bottom 
of  the  can  is  slanting  towards  the  faucet,  or  opening.  Thus 
no  water  is  permitted  to  stand  on  the  bottom  and  afford  oppor- 
tunities for  germs  to  accumulate.  On  the  inside  are  three  plates. 
One  lies  horizontally,  near  the  bottom,  and  upon  it  the  filtering- 
material  rests.  Another  lies  on  the  top  of  the  fine  sand.  Both 
of  these  plates  were  perforated  with  many  small  holes.  Near  the 
top  is  placed  a  concave  plate  with  a  hole  near  the  center.  This 
plate  directs  all  the  water  to  the  center  of  the  filter-bed,  and  thus 
the  water  gets  the  full  benefit  of  the  filtering  process.     The 


268 


CHURNING  AND  WASHING  BUTTER 


total  cost  of  this  filtering-can  when  complete  was  $11.11.  Since 
the  time  when  this  can  was  constructed  prices  have  advanced 
considerably. 

(3)  The  rate  of  filtration  is  necessarily  governed  by  the  depth 
of  the  filter-bed,  the  character  of  the  material  used,  and  its 


Fig.  100. 


Uogooogo  o 
9  K/2  ..*9t° 


Coarse  gravel  &0ob°<fe>0oS# 

n9o°9o, S°t> 
U.O0OO0S0  o  : 


3^v 


W0K 

Coke       Clj}m-V§§\ 

5 MM±$& 


&& 


Gravel     e  §;|°^f ^?£°t; 
Coarse  gravel^. 


Fig.  ioi. 


Fig.  100. — Filter-can;  1,  overflow;  2,  inlet  of  tap-water;  3,  outlet  of  filtered  water. 

Fig.  ioi. — Cross-section  of  filter-bed  and  can:  1,  overflow;  2,  inlet;  3,  outlet  of 
filtered  water;  4,  perforated  galvanized-iron  plate;  5,  perforated  galvanized- 
iron  plate;  6,  concave  galvanized-iron  plate  with  hole  in  center. 


fineness.  The  water  passes  through  the  charcoal,  coke,  and 
gravel  quite  rapidly,  yet  the  substances  are  very  strong  barriers 
to  the  passage  of  micro-organisms.  The  sand  layer  does  not 
admit  of  such  rapid  filtration.  Fine  sand,  however,  is  one  of  the 
best  filtering  substances  that  can  be  had.  The  rate  of  filtra- 
tion can  be  regulated  by  increasing  or  decreasing  the  depth  of  the 


METHODS  OF  PURIFYING  WASH-WATER  269 

fine-sand  layer.  In  a  general  way,  the  slower  the  rate  of  fil- 
tration is,  the  more  thorough  it  is;  and,  vice  versa,  the  more  rapid 
the  rate  of  filtration,  the  more  incomplete  is  the  removal  of 
the  bacteria.  If  the  filter-bed  is  constructed  as  described 
above,  the  rate  of  filtration  will  be  about  18  gallons  per  hour, 
and  about  96  per  cent  of  all  the  germs  present  will  be  removed, 
together  with  the  impurities  present  in  suspension. 

(4)  The  filter  used  at  the  Iowa  Experiment  Station  was  in 
constant  use  for  about  three  months,  without  having  been 
changed.  At  the  end  of  this  time  it  did  as  efficient  work  as 
at  any  previous  time.  The  length  of  time  a  filter-bed  can  be 
used  without  being  changed  depends  upon  the  purity  of  the 
water  to  be  filtered,  and  also  upon  which  kind  of  filtration  is 
used,  the  continuous  or  the  intermittent.  The  more  impure 
the  water  which  has  to  be  filtered,  the  oftener  the  filter-bed 
should  be  changed.  Whenever  the  rate  of  filtration  is  decreased 
to  such  an  extent  as  to  make  the  process  impracticable,  the 
filter-bed  should  be  taken  out  and  cleaned.  If  the  water  to  be 
filtered  is  of  average  purity,  a  change  of  the  filtering-material 
once  every  four  months  is  ordinarily  sufficient,  no  matter  whether 
continuous  or  intermittent  filtration  is  used.  A  filter-bed  may 
do  efficient  work  even  a  longer  time  than  this.  The  same  filter- 
ing-material can  be  used  again  providing  it  is  thoroughly  washed 
previous  to  replacing  it  in  the  filtering-can. 

Kinds  of  Filtration. — The  two  kinds  of  filtration  in  use  are 
(1)  Continuous,  and  (2)  Intermittent. 

By  the  continuous  method  of  filtration  the  inflow  of  water 
into  the  can  is  constant  during  night  and  day.  The  stream  of 
water  admitted  into  the  filter-can  is  sufficient  to  cause  the 
surface  of  the  filter-bed  to  be  covered  with  water  all  the  time. 
This  method  excludes  all  oxygen  from  the  filter-bed,  except 
that  which  is  in  solution  in  the  water. 

During  the  process  of  filtration  a  slimy  coat  is  deposited  on 
the  fine  sand.  This  seems  to  be  the  real  agent  absolutely 
necessary  in  order  to  eliminate  bacteria  by  a  process  of  filtration. 
A  filter-bed  without  this  slimy  deposit  on  it  simply  takes  out  the 
coarse  organic  and  inorganic  matter  held  in  suspension,  without 


270 


CHURNING  AND  WASHING  BUTTER 


removing  the  bacteria.  If  some  bacteria  are  removed  with 
the  matter  held  in  suspension,  others  are  carried  along  from  the 
filter-bed.  Owing  to  this,  a  new  filter-bed  must  be  kept  in 
operation  a  few  days  before  the  filtered  water  can  be  considered 
pure  and  ready  for  use.  The  following  table  illustrates  how  the 
germ-content  of  water  is  decreased  as  the  process  of  filtration  is 
carried  on  during  the  first  few  days: 


Filtered 

Unfiltered 

Water, 

Tap- water, 

Germs  per 

Germs  per 

c.c. 

c.c. 

No.  i. 

Taken  when  filter-bed  was  first  used 

20,000 

107 

No.  2. 

Taken  when  filter-bed  had  worked  1  day. .  .  . 

860 

118 

No.  3. 

Taken  when  filter-bed  had  worked  3  days .  .  . 

37o 

96 

No.  4. 

Taken  when  filter-bed  had  worked  5  days .  .  . 

48 

54 

No.  5. 

Taken  when  filter-bed  had  worked  7  days .  .  . 

3 

73 

No.  6. 

Taken  when  filter-bed  had  worked  9  days .  .  . 

5 

89 

It  will  be  seen  from  the  table  that  during  the  first  three  days 
the  filter-bed  was  in  use  the  filtered  water  contained  more 
germs  than  the  unfiltered.  Good  results  were  not  obtained 
until  the  seventh  day.  In  order  to  be  on  the  safe  side  it  is 
best  to  expose  the  filter-bed  to  continuous  filtration  for  about 
nine  days  before  the  water  is  used. 

The  slimy  coat  referred  to  above  is  formed  by  certain  germs. 
These  germs  then  constitute  the  real  agent  of  filtration.  In 
order  that  these  micro-organisms  may  do  efficient  work  oxygen 
is  essential.  Well-water  of  average  purity  contains  enough 
oxygen  in  solution  without  employing  an  intermittent  process  of 
filtration,  and  consequently  for  creamery  purposes  the  con- 
tinuous method  of  filtration  is  to  be  recommended. 

Intermittent. — The  intermittent  process  of  filtration  is  used 
where  comparatively  impure  water  is  being  purified,  such  as  in 
purifying  water  for  large  cities.  If  the  continuous  process 
of  filtration  were  employed  in  such  instances,  the  filtered  water 
would  not  be  free  from  germs,  due  to  the  fact  that  impure  river- 


METHODS  OF  PURIFYING  WASH-WATER  271 

water  does  not  carry  enough  oxygen  in  solution  to  supply  the 
germs  which  form  the  real  filtering  agency. 

If  the  intermittent  process  is  used,  the  first  water  filtered  after 
the  intervening  period  should  not  be  used.  During  the  inter- 
mission, or  during  the  time  that  the  water  is  shut  off,  germs 
develop  and  come  through  the  filter-bed  with  the  water  that  is 
filtered. 

Advantages  of  Purifying  Wash-water  for  Butter. — The  chief 
advantage  of  purifying  wash-water  for  butter  is  that  the  keeping 
quality  of  the  butter  is  improved,  and  if  the  proper  skill  and 
care  have  been  applied  in  the  other  steps  of  manufacture,  a  pure 
sanitary  product  is  obtained.  The  sanitary  efficiency  reached 
by  purifying  the  wash-water  constitutes  no  small  consideration. 
Germs  producing  contagious  diseases  are  thus  prevented  from 
spreading. 


CHAPTER  XVIII 
SALTING  AND  WORKING  OF  BUTTER 

Objects  of  Salting. — (i)  The  chief  object  in  salting  butter 
is  to  impart  a  desirable  salty  flavor.  (2)  Within  limits,  salt 
improves  the  keeping  quality  of  butter.  (3)  Salt  facilitates  the 
removal  of  buttermilk. 

Amount  of  Salt  to  Use  to  Produce  Proper  Flavor. — The  proper 
amount  of  salt  to  use  in  order  to  impart  a  desirable  flavor  depends 
chiefly  upon  the  market.  Some  consumers  prefer  a  medium 
high  salt-content  in  butter;  others,  again,  like  butter  which 
contains  very  little  salt.  The  English  market  demands  rather 
light-salted  butter.  In  fact,  this  is  the  case  with  prac- 
tically all  European  markets.  American  markets,  as  a  rule, 
demand  a  comparatively  large  amount  of  salt,  as  much  as  will 
properly  dissolve  in  the  butter.  Parisian  markets  and  some 
markets  in  southern  Germany  require  no  salt  at  all.  The  salt- 
content  of  butter  may  vary  between  nothing  and  4  per  cent. 
Butter  containing  as  much  as  4  per  cent  salt  is,  as  a  rule,  too 
highly  salted,  and  part  of  the  salt  is  usually  present  in  an  undis- 
solved condition.  Those  who  like  good  butter  prefer  the  salt 
thoroughly  dissolved  and  well  distributed. 

The  amount  of  salt  to  be  added  should  be  based  upon  the 
least  variable  factor.  Some  creamerymen  measure  the  amount 
of  salt  according  to  the  amount  of  cream  in  the  churn.  While 
the  box-churn  and  Mason  butter- worker  were  being  used,  many 
makers  preferred  to  weigh  the  butter  as  it  was  transferred  from 
the  churn  to  the  worker.  The  method  mostly  in  use  now  and  to 
be  recommended  is  to  base  the  amount  of  salt  upon  the  number 
of  pounds  of  fat.  The  amount  of  salt  to  use  per  pound  of  fat 
varies,  therefore,  according  to  the  conditions  mentioned  below, 
and  also  according  to  local  conditions.  Usually  from  half  an 
ounce  to  one  and  a  half  ounces  of  salt  per  pound  of  butter-fat 

272 


EFFECT  OF  SALT  UPON  KEEPING  QUALITIES  273 

is  most  suitable.  In  whole-milk  creameries  the  salt  is  often 
estimated  per  hundredweight  or  per  thousand  pounds  of  milk. 

To  get  the  butter  salted  uniformly  from  day  to  day  is- very 
important.  A  variation  of  i  per  cent  to  2  per  cent  in  the  salt- 
content  can  very  easily  be  detected  by  the  consumer,  while 
that  much  variation  in  any  one  of  the  other  chief  constituents 
could  not  be  readily  noticed. 

The  conditions  upon  which  the  proper  amount  of  salt  depend 
are:  First,  the  amount  and  condition  of  moisture  in  the  butter 
at  the  time  the  salt  is  added.  If  there  is  a  great  deal  of  loose 
moisture  in  the  butter,  more  salt  is  necessary.  This  is  due  to  the 
fact  that  the  salt  will  go  into  solution  in  the  water  and  be 
expressed  during  working.  Secondly,  it  depends  upon  the 
amount  of  working  the  butter  receives,  and  at  what  time  the 
bulk  of  working  is  done,  after  the  salt  has  been  added.  If  the 
butter  is  medium  firm,  moisture  in  the  form  of  brine  is  being 
expressed  during  the  working.  Consequently,  the  more  butter 
is  worked,  up  to  a  certain  limit,  the  more  brine  is  being  expressed, 
and  the  more  salt  should  be  added  to  the  butter.  Thirdly,  it 
depends  upon  the  firmness  of  the  butter,  the  size  of  the  granules, 
and  the  method  of  applying  the  salt.  If  the  granules  be  inclined 
to  be  soft  and  slushy  more  salt  must  be  added  than  would  other- 
wise be  necessary,  as  more  will  be  carried  off  during  the  process  of 
working. 

It  is  undoubtedly  due  to  these  facts  that  the  salt-content 
and  the  condition  of  salt  in  butter  vary  so  much  at  the  different 
creameries;  they  even  vary  considerably  from  one  churning 
to  another  at  the  same  creamery.  If  conditions  are  uniform  in 
the  creamery  from  day  to  day,  the  amount  of  salt  to  add  to 
butter,  and  the  amount  of  salt  retained  in  the  butter  when 
finished,  will  be  comparatively  uniform. 

It  was  thought  at  one  time  that  heavy  salting  covered  defective 
flavors  in  butter.  Such  is  not  the  case;  it  really  accentuates 
them.  Some  of  the  large  creameries  make  their  second-grade 
cream  into  sweet  or  unsalted  butter. 

Effect  of  Salt  upon  Keeping  Qualities. — Within  certain 
limits  salt  acts  as  an  antiseptic  and  improves  the  keeping  qual- 


274 


SALTING  AND  WORKING  OF  BUTTER 


ities  of  butter;  but  there  does  not  appear  to  be  any  advantage 
to  be  gained  from  heavy  salting.  We  submit  the  following  short 
tables  in  support  of  this  view,  the  first  made  up  from  investiga- 
tions by  McKay  and  Larsen  at  the  Iowa  Station  and  the  second 
from  investigations  by  Gray  of  the  U.  S.  Department  of  Agri- 
culture (Butter  scored  by  McKay) : 


Ounces  of 
Salt  to 

1  Pound 
Butter 

Scores 

Number 

When 
Made 

At  End  of 
One  Month 

At  End  of 
Two  Months 

At  End  of 
Three  Months 

Exp.  13 
Exp.  14  , 

25 

26 
27 
28 

r  29 
1 30 

0. 

0.5 
1.0 

1. 5 

0. 

1.0 

92.0 
93-5 
92-5 
92.0 

93-0 
94.0 

85.0 

87.5 
88.0 

90.S 
90.0 
89.0 

75-o 
85.0 
87.0 
84.0 
8o.S 
86.0 

65,.  0 
78.0 
80.0 
80.0 
74.0 
87.0 

Per  Cent 
of 

Scores 

Num- 

Before 

Stored  at 

-  io°  F. 

Stored  at +io°F. 

Stored  at  +  320  F. 

ber 

Storing 

Salt 

Five 

Eight 

Five 

Eight 

Five 

Eight 

Months 

Months 

Months 

Months 

Months 

Months 

Some 

individu 

al  lots: 

f  1.02 
I  3.20 

88 

93 

9°* 

92J 

90 

90 

86 

89 

90 

88 

89* 

86 

85 

84 

f   I.IO 

I  2.87 

91 

93 

912 

92 

9ii 

89 

88 

9i 

9°£ 

87 

90 

87 

88 

87 

f  2.00 
I  3.16 

912 

92i 

89 

89 

89 

9i 

88 

3 

M 

9i 

89 

90 

88* 

89 

84 

J  i-S2 
I  3.28 

91! 

9i 

88* 

9o| 

88 

88 

82 

4 

89 

89 

85 

87l 

85 

86 

80 

Avera 

ge  of  all 

Lots  in  t 

he  Exper 

iment 

: 

Light 

Salt 

1.64 

91.7 

92.6 

90.9 

91.70 

90.6 

90.3 

87.8 

Heavy 

Salt 

3-44 

91.2 

90.5 

89.9 

90.15 

89.0 

89.0 

85.0 

SALT  FACILITATES  THE  REMOVAL  OF  BUTTERMILK     275 

Each  "  experiment  "  in  the  first  table  includes  samples  of 
butter  from  the  same  churning,  salted  at  the  different  rates 
indicated. . 

Each  pair  or  lot  of  churnings  reported  in  the  second  table 
were  from  the  same  vat  of  cream. 

The  first  table  shows  that  salted  butter  keeps  better  than 
unsalted  butter.  The  second  table  shows  that  light  salting  is 
just  as  effective  for  improving  the  keeping  quality  of  butter  as 
heavy  salting.  In  fact,  in  nearly  all  cases  lightly  salted  butter 
came  out  of  storage,  at  the  end  of  eight  months,  with  a  higher 
score  than  butter  that  was  heavily  salted.  This  would  be  due 
in  part  to  the  salt  bringing  out  defects  in  flavor. 

Salt  Facilitates  the  Removal  of  Buttermilk. — That  salt 
facilitates  the  removal  of  buttermilk  can  easily  be  demon- 
strated by  observing  the  escape  of  buttermilk  from  the  butter 
immediately  after  the  salt  has  been  added  and  mixed  with  the 
butter.  The  first  effect  of  salt  when  added  to  the  butter  is  to 
precipitate  the  curd  in  the  buttermilk.  This  precipitation  is 
greater  when  a  large  amount  of  salt  is  added  than  when  only 
a  small  amount  is  added.  The  precipitation  of  the  casein  in 
the  buttermilk  sets  free  the  remainder  of  the  buttermilk  con- 
stituents; that  is,  when  the  casein  is  precipitated,  the  whey 
part  assumes  a  more  fluid  condition  and  escapes,  and  the  butter 
retains  a  portion  of  the  curd.  Owing  to  this  action  of  the  salt, 
it  is  essential  that  the  butter  should  be  as  completely  washed  as 
possible,  as  otherwise  it  will  retain  an  excessive  amount  of  curd. 
The  butter  acts  in  a  manner  somewhat  similar  to  a  filter  in 
removing  a  part  of  the  curd  from  the  other  buttermilk  con- 
stituents. 

Salt  in  Relation  to  Water  in  Butter. — Experiment  has  dem- 
onstrated that  pure  fat  is  not  a  salt-dissolving  substance.  Owing 
to  this  fact  the  only  salt-dissolving  substance  in  butter  is  water. 
As  water  will  hold  only  a  certain  amount  of  salt  in  solution,  it 
becomes  evident  that  the  amount  of  salt  which  can  be  properly 
incorporated  in  butter  depends  upon  the  amount  of  moisture 
present. 

The  amount  of  salt  which  water  will  hoia  in  solution  at 


276 


SALTING  AND   WORKING  OF  BUTTER 


different  temperatures  varies  somewhat  according  to  different 
investigators.  According  to  Gerlach x  water  will  dissolve 
35.94  per  cent  salt  at  58 °  F.  This  is  approximately  the  tem- 
perature at  which  salt  is  worked  into  butter.  Theoretically, 
butter  containing  15  per  cent  of  water  should  be  able  to  properly 
dissolve  5.4  per  cent  of  salt.  Butter  containing  13  per  cent  of 
water  should  be  able  to  properly  dissolve  4.68  per  cent  of  salt, 
and  butter  containing  10  per  cent  of  water  should  be  able  to  dis- 
solve properly  3.6  per  cent  of  salt,  etc.     According  to  experiments 


Fig.  102. — Action  of  salt  solutions  of  different  strength  on  the  proteids  of  butter- 
milk.    (Bui.  263,  Gen.,  N.  Y.) 

conducted  at  the  Iowa  Experiment  Station  the  maximum  per 
cent  of  pure  salt  (Na.Cl)  that  could  be  properly  dissolved  in  water 
of  butter  containing  16.92  per  cent  of  moisture,  when  worked  18 
revolutions  at  intervals  during  two  hours,  was  16.57  Per  cent- 
When  butter  was  worked  the  same  number  of  revolutions  at 
intervals,  and  was  allowed  to  dissolve  only  one  hour,  the  amount 
of  pure  salt  (NaCl)  that  was  dissolved  in  the  water  of  the  butter 
containing  11.58  per  cent  moisture  was  14.09  per  cent.  This 
undoubtedly  will  vary  with  different  brands  of  salt. 
1  Kemiker-Kalender,  p.  219. 


KIND   AND   CONDITION   OF   SALT 


277 


It  will  thus  be  seen  that  the  property  of  water  to  take  up 
salt  is  seemingly  lessened  when  the  water  is  present  in  a  state 
of  minute  division,  as  it  is  in  butter.  In  the  first  instance 
quoted  the  butter  completely  dissolved  about  2.7  per  cent  of  pure 
salt;  and  in  the  second  instance  it  dissolved  only  about  2  per 
cent  during  one  hour. 

From  the  foregoing  it  is  evident  that  where  butter  contains  a 
high  per  cent  of  salt,  the  salt  is  not  thoroughly  dissolved. 

Kind  and  Condition  of  Salt. — Salt  for  butter  should  be  fine 


Fig.  103. — Volumes  of  the  same  weight  of  salt  of  various  brands. 
(Bui.  74,  Wis.) 


and  readily  soluble,  so  that  it  will  be  completely  dissolved  and 
incorporated  when  the  working  of  the  butter  is  completed.  But 
fineness  alone  does  not  determine  solubility;  some  salts  that  do 
not  seem  very  fine  are  quite  readily  soluble,  because  the  crystals 
are  somewhat  flat  and  flaky  and  dissolve  quite  quickly.  Again, 
good  dairy  salt  is  clean  and  white  in  appearance.  When  it  is 
dissolved  in  a  cylinder  of  water  there  should  be  no  settlings  and 
nothing  left  floating  on  the  surface  of  the  water. 

Some  salt  is  chemically  impure,  one  of  the  impurities  being 
magnesium  chloride,  which,  when  present  to  any  extent,  imparts 
a  bitter  flavor  to  butter.     Good   butter  salt  is  practically  free 


278  SALTING  AND  WORKING  OF   BUTTER 

of  this  impurity.     According  to  analysis  of  the  best  daiiy  salt 
used  in  Denmark,  the  composition  is  as  follows:1 

Per  Cent 

Pure  salt  (sodium  chloride  (NaCl)) 97-49 


Magnesium  chloride  (MgCk) 

Gypsum  (calcium  sulphate  (CaS04)) 

Sodium  sulphate 

Water 2 


18 

05 
21 
07 


100 . 00 
The  purest  American  dairy  salt  has  the  following  composition  :2 

Per  Cent    * 

Pure  salt 99 .  18 

Magnesium  chloride 05 

Gypsum 54 

Calcium  chloride  (CaCU) 19 

Insoluble  matter 03 

Moisture 01 


100.00 


Good,  moisture-free  salt  will  contain  99  per  cent  or  over  of 
sodium  chloride  (NaCl).  Any  substance  other  than  this  is  an 
impurity  to  the  extent  to  which  it  occurs. 

Salt  readily  absorbs  odors  and  moisture.  Hence  it  should 
be  kept  in  a  clean  dry  place. 

Gritty  Butter. — "  Gritty  butter  "  is  a  familiar  phrase  used 
by  expert  butter-scorers  to  indicate  that  part  of  the  salt  is 
present  in  an  undissolved  condition.  To  most  consumers  this 
condition  of  the  salt  in  butter  is  objectionable.  When  properly 
incorporated,  salt  should  be  present  in  the  form  of  a  solution 
in  the  butter.  The  gritty  condition  of  the  salt  in  butter  may  be 
due  to  (1)  poor  condition  of  the  salt  before  it  is  added  to  the 
butter;  (2)  adding  so  much  salt  that  it  cannot  be  dissolved  by 
the  water  in  the  butter.     The  maximum  amount  of  salt  that 

1  Boggild,  Maolkeribruget,  Denmark. 

2  Bui.  No.  74,  Wis.,  by  F.  W.  Woll. 


MOTTLED   BUTTER 


279 


butter  will  dissolve  depends  upon  the  amount  of  moisture  present. 
The  maximum  amount  of  moisture  permissible  in  butter,  accord- 
ing to  the  Treasury  ruling,  is  16  per  cent.  The  condition  of  the 
water  in  butter  prevents  the  water  from  being  saturated  with 
salt  during  the  comparatively  short  time  allowed  for  salt  to 
dissolve  during  the  manufacture  of  butter.  (3)  Insufficient 
working.  If  the  butter  is  not  worked  enough  to  distribute 
the  salt  evenly,  some  portion  of  the  butter  will  contain  more 
than  the  other  portions.     The  portion  that  contains  the  excess 


^*& 


♦  • 


♦  #' 


Fig    104. — Worcester  salt.  Fig    105. — Diamond  crystal  salt. 

Types  of  crystals  of  buttersalts. 


of  salt  does  not  have  enough  moisture  to  dissolve  the  salt;  while 
if  the  salt  had  been  evenly  distributed  in  the  butter,  all  the  salt 
would  have  been  properly  dissolved.  When  gritty  butter  is 
caused  by  insufficient  working,  it  usually  mottles. 

Mottled  Butter. — Mottled  butter  is  butter  which  is  uneven 
in  color.  This  may  be  due  to  different  causes.  The  most  com- 
mon cause,  however,  is  failure  to  get  the  salt  properly  dissolved 
and  evenly  distributed  by  the  time  the  working  of  the  butter  is 
completed. 


280  SALTING  AND   WORKING  OF   BUTTER 

The  causes  and  remedies  for  mottles  are  pretty  thoroughly 
understood  by  almost  all  up-to-date  butter-makers.  Twenty 
or  twenty-five  years  ago  mottles  constituted  one  of  the  leading 
defects  found  in  the  creamery  butter  supplied  to  our  markets. 
Charles  Y.  Knight,  then  editor  of  Chicago  Dairy  Produce, 
offered  a  series  of  prizes  for  the  best  methods  of  preventing 
mottled  butter,  and  many  creamerymen  entered  the  competition. 
The  result  was  that  a  lot  of  valuable  information  was  obtained, 
which  resulted  to  a  very  large  extent  in  preventing  mottled  but- 
ter. Many  theories  have  been  advanced  as  to  both  the  cause  and 
the  remedy  for  mottles. 

Long  before  creameries  were  established  some  farmers' 
wives  had  mastered  the  art  of  butter-making  to  the  extent*  that 
they  produced  butter  of  a  uniform  quality  free  from  mottles. 
This  was  accomplished  by  their  methods  of  working.  Possibly 
they  had  no  knowledge  of  what  actually  caused  mottles,  but 
they  knew  that  if  they  worked  the  butter  sufficiently  to  thor- 
oughly incorporate  the  salt  mottles  would  not  appear  in  the  fin- 
ished butter. 

Drs.  Van  Slyke  and  Hart  say  that  if  the  proteids  are  thor- 
oughly washed  from  the  butter,  mottles  cannot  be  produced,  no 
matter  how  unevenly  the  salt  is  distributed.  Complete  removal 
of  the  buttermilk  by  washing  is  one  of  the  essentials  in  preventing 
mottles  in  butter. 

Storch  made  an  extensive  study  of  the  causes  of  mottles 
in  butter.  He  claims  that  the  water  in  butter  is  present  in 
two  forms  or  conditions.  There  is  the  water  which  is  con- 
tained in  the  form  of  an  extremely  fine  emulsion  in  the  nitro- 
genous material  composing  the  film  surrounding  the  fat  globules ; 
and  there  is  the  water  which  is  enclosed  by  the  granules  as  they 
form  or  is  picked  up  later  from  the  buttermilk  or  the  wash- water, 
and  which  is  present  in  the  finished  butter  in  the  form  of  larger 
droplets,  or  a  much  coarser  emulsion.  The  whitish,  opaque 
dapples,  Storch  claims,  are  due  to  the  fine  emulsion  of  water 
in  the  nitrogenous  material  referred  to,  and  the  yellow,  clearer 
markings  to  the  larger  droplets  of  water  picked  up  from  the 
buttermilk  and  wash-water. 


MOTTLED   BUTTER  281 

Sammis  and  Lee  repeated  a  portion  of  Storch's  investiga- 
tion. They  found  that  butter-fat,  freed  from  casein  by  melting 
and  filtration,  then  emulsified  with  water  and  churned,  pro- 
duced typical  mottles  when  the  salt  was  not  evenly  distributed 
throughout  the  mass.  They  thus  produced  mottles  entirely 
independent  of  the  casein.  Microscopic  examination  of  such 
butter  showed  similar  results  as  in  the  case  of  Storch's  experi- 
ment. In  the  portions  which  were  lighter  in  color,  the  water 
was  present  in  the  form  of  innumerable  small  droplets,  while 
in  the  portions  that  were  darker,  the  droplets  of  water  were  much 
larger.  No  counts  nor  measurements  of  the  droplets  were  given. 
These  investigators  emphasize  the  importance  of  thorough 
working  of  the  butter  to  prevent  the  mottled  appearance. 

The  mottles  caused  by  improper  incorporation  of  salt  assume 
two  different  forms,  viz.,  mottles  proper,  and  wavy  butter.  As 
has  been  mentioned  before,  the  mottles  result  from  undissolved 
salt.  Whenever  there  is  undissolved  granular  salt  present,  the 
moisture  is  attracted  and  the  color  deepened  at  that  particular 
place.  In  case  the  water  has  already  been  saturated  with  salt, 
there  is  no  danger  of  mottles,  no  matter  how  much  gritty  salt  is 
present. 

Mottles  do  not  affect  the  quality  of  butter,  but  the  consuming 
public  desire  uniformity  in  color.  For  this  reason  butter  is 
artificially  colored  during  the  winter  months  when  cows  are 
on  dry  feed  which  is  not  conducive  to  the  production  of  a  yellow 
color  in  the  butter.  Many  people  like  the  appearance  of  marble 
cake;  the  same  people  would  seriously  object  to  marbled  butter. 

The  salt  which  is  placed  on  butter  or  mixed  with  it  has  an' 
affinity  for  water.  Therefore,  the  droplets  of  water  are  attracted 
to  the  granules  of  salt.  The  result  is  that  a  certain  portion  of 
the  butter  assumes  a  dark  appearance,  possibly  somewhat 
similar  to  the  clouds  appearing  before  a  rainstorm;  or,  in  other 
words,  mottles  may  be  said  to  be  caused  by  the  uneven  distribu- 
tion of  the  water  droplets. 

It  will  be  observed  that  the  white  streaks  in  butter  contain 
little  or  no  salt.  Professor  O.  F.  Hunziker  has  done  very 
extensive  work  on  this  subject.     The  white  opaque  places  in 


282  SALTING  AND  WORKING  OF  BUTTER 

mottled  butter  are  caused  by  the  localization  of  innumerable 
very  small  water  droplets. 

There  are  a  number  of  things  that  have  a  tendency  to  cause 
mottles.  In  the  early  spring,  when  the  cows  are  changed  from 
dry  feed  to  grass,  mottles  are  more  prevalent  than  at  any  other 


Fig.  106. — Imperfect  working,  due  to  overloading  churn,  and  causing  a  portion 
of  the  butter  to  fall  over  the  rolls  without  being  worked,  has  a  tendency  to 
cause  mottles  and  uneven  distribution  of  moisture. 

season  of  the  year.  This  is  due  to  the  presence  of  an  increased 
per  cent  of  the  low-melting  fats  in  butter.  The  butter  has  a 
tendency  to  be  slushy  or  soft  and  the  granules  of  salt  appear  to 
be  imbedded  in  the  butter  and  do  not  dissolve  as  readily. 

This  defect  may  be  overcome  by  churning  at  a  sufficiently 
low  temperature.     The  butter  granules  will  then  gather  into  a 


MOTTLED   BUTTER 


283 


firm  enough  mass  to  be  efficiently  worked.  In  small  creameries 
where  only  one  or  two  churnings  are  to  be  made  the  butter  can 
be  worked  enough  to  mix  the  salt  thoroughly  throughout~the 
mass  and  permitted  to  stand  for  an  hour,  when  the  working  may 


V 


Fig.  107. — Imperfect  working,  due  to  overloading  churn,  and  causing  a  portion 
of  the  butter  to  fall  over  the  rolls  without  being  worked,  has  a  tendency  to 
cause  mottles  and  uneven  distribution  of  moisture. 


be  completed.     This  is  a  method  that  has  been  used  by  some 
buttermakers  for  a  great  many  years. 

The  system  used  in  Denmark  a  number  of  years  ago,  when  one 
of  the  authors  was  visiting  that  country  investigating  creamery 
conditions,  was  to  mix  the  salt  thoroughly  with  the  butter  on 
the  table  worker ;  then  cut  the  butter  up  into  large  rolls  and  place 


284  SALTING  AND  WORKING  OF  BUTTER 

it  in  a  tank  of  water  at  a  temperature  of  6o°  F.,  and  permit  it  to 
stand  there  for  two  hours;  then  take  the  butter  out  and  finish 
working  it.  This  had  the  effect  of  giving  the  entire  mass  of 
butter  a  uniform  temperature  and  it  gave  sufficient  time  to  get 
the  salt  quite  thoroughly  dissolved  before  completion  of  the  final 
working. 

Quite  a  common  cause  of  mottles,  particularly  in  the  summer 
months,  is  the  overloading  of  churns.  Part  of  the  butter 
falls  over  the  rolls  instead  of  passing  through  them.  Working 
butter  under  these  conditions  will  not,  as  a  rule,  produce  either  a 
uniform  color  or  a  uniform  distribution  of  moisture.  Where  the 
rolls  are  out  of  alignment  it  also  has  a  tendency  to  result  in 
uneven  working  and  thus  cause  mottles. 

Washing  the  butter  with  very  cold  water  which  chills  the 
surface  of  the  granules  also  has  a  tendency  to  produce  mottles. 
Butter  does  not  appear  mottled  when  first  taken  from  the  churn. 
On  standing  the  more  loosely  held  large  water  droplets  run 
together  into  larger  aggregates  and  the  portions  of  the  butter 
containing  these  fewer  but  larger  droplets  show  deeper  yellow  in 
color. 

Prevention  of  Mottles  in  Butter. — To  state  the  cause  or  causes 
of  a  defect  is  often  to  suggest  the  remedy  or  remedies,  in  a 
large  measure.  Unsalted  butter  is  never  mottled.  This  is,  in 
itself,  very  suggestive.  It  is  well  known  to  experienced 
creamerymen,  and  has  been  taught  in  our  dairy  schools  for 
years,  that  butter  will  be  neither  mottled  nor  streaked  if  the 
salt  is  thoroughly  dissolved  and  the  brine  evenly  distributed  and 
incorporated  in  fine  particles  or  droplets  in  the  butter  by  the 
time  we  are  through  working  it.  There  are  several  means  which 
further  this  end,  and  these  may  be  briefly  stated  as  follows: 

Have  the  cream  at  the  right  temperature  for  churning. 
The  butter  will  then  come  in  good  condition.  It  will  be  reason- 
ably firm  and  the  buttermilk  can  be  washed  out  of  it  thoroughly. 

Have  the  wash-water  at  the  right  temperature,  so  that  the 
butter  will  be  in  good  condition  for  working.  It  can  then  be 
worked  sufficiently  to  insure  the  end  sought  without  injuring  the 
grain  and  body  of  the  butter. 


CURDY  SPECKS  IN  BUTTER 


285 


See  that  the  worker  is  in  good  condition.  The  space  between 
the  rolls,  from  end  to  end  of  the  churn,  should  be  the  same; 
they  should  be  properly  set  and  in  perfect  alignment,  and  there 
should  be  no  looseness  in  the  bearings  and  no  slipping.  The 
rolls  should  be  straight  or  without  any  warps  in  them,  and  so 
set  that  the  elevations  on  the  one  meet  the  grooves  of  the  other. 


Fig.  108. — Rolls  out  of  alignment. 

The  same  care  must  be  taken  with  regard  to  the  relation  of  the 
roll  to  the  shelf  in  single-roll  churns. 

Use  a  good  quality  of  salt  that  will  dissolve  readily,  and 
distribute  it  in  the  butter  as  evenly  as  possible  from  end  to 
end  of  the  churn. 

Do  not  make  too  large  a  churning.     This  means  overloading 


Fig.  109. — Rolls  perfect. 


Fig.  i  10. — Rolls  not  meshing,  causing 
imperfect  working. 


the  workers,  and  as  a  consequence  part  of  the  butter  falls  over 
the  rolls  and  is  not  worked. 

If  mottles  develop  in  butter  they  can  be  eliminated  by  rework- 
ing it.  But  this  is  a  remedy  that  it  should  not  be  necessary 
to  apply  very  often. 

Curdy  Specks  in  Butter. — Curdy  specks  are  not,  properly 
speaking,  mottles.     We  should  make  a  sharp  distinction  between 


286  SALTING  AND  WORKING  OF  BUTTER 

the  two.  Curdy  specks,  as  the  term  implies,  are  small  white 
particles  of  curd  throughout  the  butter  that  are  visible  to  the 
naked  eye.  Overripening  of  either  the  starter  or  the  cream  may, 
and  probably  will,  produce  curd  particles  that  will  show  in  the 
butter,  especially  if  the  cream  is  not  strained  into  the  churn 
through  a  fine  strainer.  Avoid  these  faulty  conditions;  break 
up  and  mix  the  starter  thoroughly  before  putting  it  into  the 
cream;  and  strain  the  starter  into  the  cream  and  the  cream  into 
the  churn. 

To  insure  uniform  salting  it  is  advisable  to  bring  the  butter 
up  on  the  shelf  and  rolls,  make  a  trench  in  it  from  end  to  end 
of  the  churn — leaving  both  ends  closed — and  distribute  the  salt 
evenly  along  the  trench.  Should  the  butter  be  in  a  very  firm 
condition  a  little  water  should  be  added  to  the  salt.  The 
trench  is  then  closed  so  as  to  cover  the  butter  before  the  workers 
are  started. 

As  butter  is  worked  it  becomes  an  aggregation  of  butter 
granules  with  the  intervening  spaces  occupied  by  water,  curd  and 
air.  The  more  butter  is  worked  the  smaller  the  intervening 
spaces.  On  the  broken  surfaces  of  worked  butter  and  under  the 
microscope  the  water  appears  in  the  form  of  round  droplets. 
The  less  the  butter  is  worked  the  larger  the  drops  and  the  more 
ragged  the  break  or  grain.  The  more  the  butter  is  worked  the 
smaller  the  droplets  of  water  and  the  shorter  the  grain.  If  the 
working  of  butter  continues,  air  to  the  extent  of  10  per  cent  or 
less  by  volume  is  incorporated. 

When  a  piece  of  butter  is  torn  from  the  partly  worked  mass 
its  broken  surface  is  very  irregular  and  shows  large  drops  of 
water,  like  tears.  Upon  squeezing,  a  shower  of  water  falls  out 
of  the  butter.  If  packed  in  this  condition  the  butter  would  leak. 
As  the  working  progresses  the  drops  become  smaller  and  smaller 
and  fewer  can  be  squeezed  out  of  a  piece.  The  working  has 
produced  the  desired  end  when  the  broken  surface  sparkles  with 
small  droplets  of  water  like  pinheads  and  only  two  or  three  drops 
fall  out  upon  squeezing.  If  packed  at  this  stage  the  butter  has  a 
beautiful  grain  and  does  not  leak;  but  if  worked  beyond  this 
point  the  droplets  of  water  disappear,  the  grain  becomes  short 


BRINE-SALTING  287 

and  the  butter  becomes  greasy,  air  is  incorporated,  and  the 
color  is  light,  dull  and  lusterless.  Such  butter  is  overworked 
and  keeps  poorly.  —   - 

The  process  of  working  grinds  up  the  water  in  the  butter  into 
smaller  and  smaller  drops.  In  a  leaky  butter  the  water  is 
present  in  large  drops;  in  a  dry  butter  it  is  present  in  small  but 
numerous  drops.  Repeated  working  does  not  injure  the  grain  so 
long  as  drops  of  water  can  be  seen  on  the  torn  surface.  Logically 
the  working  of  butter  should  be  continued  until  the  butter  is  not 
leaky  and  stopped  before  it  is  dry  and  sticky. 

Brine-salting. — Brine-salting  is  not  as  a  rule  practiced  in 
creameries.  It  is  too  expensive  a  method  of  salting,  and  also 
too  laborious.  By  salting  butter  with  brine  it  is  hardly  possible 
to  get  in  salt  enough  to  suit  the  American  butter  markets,  2 
per  cent  being  about  the  maximum  amount  of  salt  that  can  be 
incorporated  by  the  brine  method. 

In  some  instances,  brine-salting  has  been  recommended.  If 
a  light  mild  taste  is  desired,  the  brine  method  may  give  good 
results.  The  greatest  advantages  of  brine-salting  are  that 
mottles  in  butter  are  practically  avoided,  and  that  the  overrun 
is  usually  increased  a  trifle.  Especially  is  this  so  if  the  tempera- 
ture of  the  brine  is  medium  high  when  added  to  the  butter.  In 
order  to  get  enough  salt  (2  per  cent)  into  the  butter  by  the  brine 
method,  it  is  necessary  to  churn  it  considerably  in  the  brine  and 
to  use  two  sets  of  brine.  When  brine  is  first  added  the  butter 
already  contains  considerable  water.  This  water  practically 
has  to  be  replaced  by  brine.  This  is  difficult  to  do,  especially  if 
the  butter  has  been  overchurned  a  trifle. 

Churning  the  butter  in  the  first  brine  will  soon  dilute  the  brine 
to  such  an  extent  that  it  will  impart  but  little  saltiness  to  the 
butter.  For  this  reason  this  first  brine  should  be  removed  and 
another  one  added,  and  the  butter  churned  again  in  this  brine. 
This  last  brine  will  have  very  little  curd  in  it,  and  can  be  saved 
until  the  following  day  and  then  used  as  the  first  brine.  The 
first  brine  may  be  used  each  day  for  soaking  tubs. 

It  is  essential  to  leave  the  brine  on  the  butter  for  from  five 
to  fifteen  minutes.     Churning  excessively  in  the  brine,  espe- 


288  SALTING  AND  WORKING  OF  BUTTER 

daily  if  butter  is  medium  soft,  will  cause  too  much  water  to  be 
incorporated  in  the  butter.  After  the  butter  has  been  exposed 
to  the  second  brine  the  proper  length  of  time,  it  should  be  drawn 
off  and  the  butter  worked  in  the  usual  manner.  Less  working 
is  usually  given  to  butter  which  has  been  salted  by  the  brine 
method.  It  should  be  worked  enough  to  distribute  the  brine 
evenly  in  the  butter,  and  to  bring  the  butter  into  a  compact  form. 
If  the  butter  salted  by  the  brine  method  is  not  worked  sufficiently, 
it  will  become  streaky  in  color  after  standing. 

SALT  TEST 

Principle  of  the  Test.  -The  reagent  used  is  a  solution  of  silver 
nitrate  (AgNOs),  and  the  indicator  is  a  solution  of  potassium 
chromate  (K2CrC>4).  The  silver  nitrate  will  combine  with 
either  common  salt  (NaCl)  or  potassium  chromate,  but  it  has  the 
stronger  affinity  for  salt.  Hence,  if  we  add  a  few  drops  of  the 
potassium  chromate  to  a  solution  of  common  salt,  and  then 
gradually  add  silver  nitrate  solution,  the  silver  nitrate  will  com- 
bine with  the  salt,  forming  white  or  colorless  compounds.  But 
as  soon  as  the  salt  is  all  used  or  taken  up  the  silver  nitrate  com- 
bines with  the  indicator,  potassium  chromate,  producing  a 
brick-red  compound. 

Chemical  Changes  that  Take  Place. — First,  as  long  as  there  is 
free  salt:  AgNC>3  (silver  nitrate)  +NaCl  (common  salt)=AgCl 
(silver  chloride) +NaNC>3  (sodium  nitrate).  No  colored  sub- 
stances formed.  Second,  after  all  the  salt  has  been  acted  upon — 
2AgN03+K2Cr04  (potassium  chromate)  =  Ag2Cr04  (silver  chro- 
mate, brick-red)  +  2 KNO 3.     Brick-red  color  produced. 

Proportions  in  which  Silver  Nitrate  and  Salt  Combine  with 
Each  Other- 
Molecular  weight  of  silver  nitrate, 

AgN03  =  108  +  14+3  X 16  =  170 

Molecular  weight  of  common  salt, 

NaCl  =  23+35.5  =  58.5 
Both  are  univalent. 


SALT  TEST  289 

Hence, 

58.5  grams  salt  combine  with  170  grams  silver  nitrate. 

1    gram  salt  combines  with  — —  =  2 .  906  grams  silver  nitrate, 

0  '  0 
or 

.01  gram  salt  combines  with  .02906  gram  silver  nitrate. 

Features  of  Practical  Salt  Tests. — The  same  principle  applies 
to  the  various  salt  tests.  In  the  different  practical  tests,  com- 
binations are  worked  out  which  enable  us  to  read  the  per  cent  of 
salt  directly,  without  having  to  make  any  mathematical  calcu- 
lations. 

The  following  combination  enables  us  to  read  the  per  cent 
of  salt  in  butter  directly  : 

(1)  29.06  (  =  29.0)  grams  of  silver  nitrate  in  a  solution  made 
up  to  1000  c.c. 

(2)  Burette  for  silver  nitrate  solution  graduated  in  cubic 
centimeters  and  tenths  of  a  cubic  centimeter. 

(3)  10  grams  of  butter,  with  the  salt  solution  from  it  made  up 
to  250  c.c. 

(4)  25  c.c.  of  the  salt  solution,  taken  by  means  of  a  25  c.c. 
pipette,  that  is,  a  tenth  of  the  salt  solution,  or  a  tenth  of  the  salt 
in  the  10-gram  sample  of  butter. 

In  1000  c.c.  of  silver  nitrate  solution  there  are  29.06  grams  of 
silver  nitrate. 

In  1  c.c.  of  silver  nitrate  solution  there  is  .02906  gram  silver 
nitrate. 

But  we  have  already  shown  that  .02906  gram  silver  nitrate 
reacts  with  .01  gram  of  salt. 

.01  gram  salt  in  25  c.c.  salt  solution  =  .1  gram  salt  in  250  c.c. 
of  salt  solution,  or  in  10  grams  butter,  which  is  1  per  cent 
of  salt. 

Hence,  each  cubic  centimeter  of  the  silver  nitrate  solution 
required  in  making  the  test  indicates  1.0  per  cent  of  salt  in 
the  butter. 


290  SALTING  AND  WORKING  OF  BUTTER 

To  Make  a  Salt  Test. — Either  weigh  out  10  grams  of  butter, 
or  take  the  residue  from  the  10  grams  of  butter  used  in  the  mois- 
ture test;  and  rinse  thoroughly  into  a  suitable  flask,  with  a  250 
c.c.  mark  on  it,  using  distilled  water  at  a  temperature  of  no° 
to  1200  F.  for  the  purpose,  and  making  up  to  250  c.c.  with  dis- 
tilled water  at  the  same  temperature.  Mix  thoroughly  to  dis- 
solve all  the  salt. 

25  c.c.  of  the  salt  solution  are  then  transferred  to  a  white 
enamel  cup,  and  to  this  are  added  2  to  3  drops  of  indicator  (a 
10  per  cent  solution  of  potassium  chromate)  from  a  brown  glass 
dropping  bottle. 

The  silver  nitrate  solution  is  then  added  from  a  burette,  and 
mixed  as  it  is  added,  until  a  permanent,  light  brick-red  color 
appears. 

Note  the  quantity  of  silver  nitrate  solution  required  to 
make  the  test.  If,  for  example,  it  requires  2.7  c.c.  of  silver 
nitrate  solution  to  make  the  test,  this  indicates  that  there  is 
2.7  per  cent  of  salt  in  the  butter;  if  it  takes  3.8  c.c.  of  silver 
nitrate  solution,  the  per  cent  of  salt  in  the  butter  is  3.8,  etc. 

Note. — If  the  salt  solution  were  made  up  to  100  c.c.  instead 
of  250  ex.,  we  could  take  10  c.c.  instead  of  25  c.c.  of  this  solution 
to  a  test  and  read  the  per  cent  of  salt  direct,  just  as  above.  In 
both  cases  we  take  a  tenth  of  the  solution  or  a  tenth  of  the  salt 
in  the  10-gram  sample  of  butter. 

Another  combination  that  will  read  the  per  cent  of  salt 
directly: 

(1)  A  tenth  normal  (N/10)  solution  of  silver  nitrate,  that  is, 
17  grams  of  silver  nitrate  in  1000  c.c.  of  the  solution.  (The 
molecular  weight  of  silver  nitrate  being  170,  there  are  170  grams 
in  1000  c.c.  of  a  normal  solution,  and  a  tenth  of  this  in  a  tenth 
normal  solution.) 

(2)  10  grams  of  butter,  the  salt  in  it,  being  dissolved  in 
300  c.c.  of  water. 

(3)  By  means  of  a  17.6  c.c.  pipette  we  take  17.5  c.c.  of  the 
salt  solution  to  a  test. 

Each  c.c.  of  silver  nitrate  solution  required  to  make  the  test 
indicates  1  per  cent  of  salt  in  the  butter. 


WORKING  OF  BUTTER  291 

Distilled  water  should  be  used  in  making  the  reagents  and 
for  the  test.  The  reagents  should  be  kept  in  brown  glass  bottles 
and  out  of  strong  light.  _. 

It  is  not  advisable  to  make  up  more  than  about  a  month's 
supply  of  silver  nitrate  solution  at  a  time. 

WORKING  OF  BUTTER 

Objects. — The  objects  of  working  butter  are: 
(i)  To  distribute  the  salt  and  brine  evenly  in  the  butter. 
The  number  of  revolutions  in  the  churn  necessary  to  accom- 
plish this  will  vary  somewhat  according  to  the  conditions  of 
the  butter,  and  according  to  the  kind  of  butter-workers  employed. 
If  the  butter  is  of  medium  firmness,  about  twelve  revolutions  in 
the  Victor  Combined  Churn  will  usually  distribute  the  salt 
properly,  providing  the  working  is  well  distributed  over  the 
working  period.  It  used  to  be,  and  is  still,  the  practice  in 
creameries  to  add  the  salt  while  the  butter  is  in  a  hard  granular 
condition,  and  then  rotate  the  churn  several  times  in  slow  gear 
without  putting  the  workers  in  gear.  This  is  done  in  order  to 
mix  the  salt  thoroughly  without  working.  Then  it  is  allowed 
to  stand  for  five  or  ten  minutes,  then  worked  about  four  revolu- 
tions and  allowed  to  stand  a  little  while  again,  then  the  working 
is  completed  by  allowing  the  churn  to  revolve  four  or  five  times 
more,  or  as  many  as  is  deemed  necessary  to  bring  the  butter  into 
proper  condition. 

It  has,  however,  been  demonstrated  that  it  is  not  advisable 
to  add  the  salt  while  the  butter  is  in  this  hard  granular  form. 
The  butter  should  be  united  into  larger  irregular  granules  before 
the  salt  is  added.  If  the  salt  is  added  to  the  butter  in  a  more 
or  less  gathered  condition,  the  workers  should  be  put  in  gear  at 
once,  for  otherwise  the  salt  will  be  scattered  on  the  inside  of  the 
churn.  Butter  can  be  worked  three  or  four  revolutions  and 
then  allowed  to  stand  until  the  salt  is  almost  dissolved,  at  which 
time  the  working  can  be  completed  by  revolving  the  churn  four 
or  five  revolutions  more.  Some  prefer  to  work  a  little  more 
than  ten  revolutions  in  order  to  be  sure  that  the  salt  has  been 
evenly  distributed. 


292  SALTING  AND   WORKING  OF  BUTTER 

If  the  Disbrow  churn  is  being  used,  it  is  necessary  to  work 
the  butter  a  greater  number  of  revolutions  than  that  recom- 
mended when  the  Victor  churn  is  used.  In  the  Victor  churn 
the  butter  is  virtually  worked  twice  at  every  revolution,  while 
in  the  Disbrow  churn  the  butter  is  only  worked  once  for  about 
three-quarters  of  a  revolution.  From  sixteen  to  twenty  revolu- 
tions of  the  Disbrow  churn  usually  mix  the  salt  with  the  butter 
properly.     It  is  impossible  to  state  exactly  the  number  of  revo- 


Fig.  in. — Old-style  table  butter-worker. 

lutions  butter  should  be  worked,  as  it  varies  according  to  different 
conditions. 

(2)  Butter  is  worked  in  order  to  bring  it  into  a  compact  form. 
When  butter  is  soft  it  usually  gathers,  but  if  it  is  present  in  the 
firm  granular  condition,  which  condition  results  from  churning 
thin  cream  and  washing  the  butter  in  cold  water,  it  is  more  or 
less  difficult  to  get  the  little  granules  together.  More  working  is 
necessary  when  the  butter  is  in  such  a  condition. 

(3)  The  working  of  butter  also  expresses  an  excessive  amount 


WORKING  OF  BUTTER  293 

of  buttermilk  or  water  that  may  be  present.  By  adding  salt 
and  then  working  the  butter,  the  excess  of  buttermilk  is  largely 
eliminated.  Especially  is  this  so  when  the  butter  is  in  a  medium 
firm  condition.  Working  is  also  effective  in  removing  water 
from  the  butter. 

Moisture  Tests  of  Butter. — i.  Official  Method. — "Weigh  1.5 
to  2.5  grams  of  the  sample  into  a  flat-bottomed  dish,  having  a 
surface  of  at  least  20  sq.  cm.,  dry  at  the  temperature  of  boiling 
water  and  weigh  at  hourly  intervals  until  the  weight  becomes 
constant.     The  use  of  clean  dry  sand  or  asbestos  is  admissible. " 

2.  Rapid  Method. — The  moisture  tests  used  in  creameries 
differ  from  the  official  method,  mainly,  in  the  speedier,  less 
refined  scales  used,  and  larger  sample  taken  to  a  test,  and  in  the 
adoption  of  a  higher  temperature  for  driving  the  moisture  off 
more  quickly.  The  results,  when  the  work  is  carefully  done,  are 
quite  reliable. 

To  Make  a  Test. — Obtain  an  average  composite  sample  from 
the  churn,  through  scraping  off  the  surface  of  the  butter  with  a 
ladle  and  taking  samples  from  end  to  end  of  the  churn  by  means 
of  a  dry.  warm  spatula  or  spoon.  In  case  of  a  tub  take  a  core 
with  a  trier,  extending  diagonally  from  top  to  bottom  of  the 
package,  and  make  up  a  composite  sample  from  sections  of  this. 
The  composite  sample  jar  should  have  a  close  cover. 

Carefully  warm  the  sample  until  the  butter  is  of  a  pasty  or 
creamy  consistency  and  mix  well  with  a  spatula. 

Weigh  10  grams  into  a  well-dried  light  aluminum  cup  about 
2§  in.  in  diameter.  Place  the  cup  on  an  asbestos  sheet  over  a 
low  gas  or  alcohol-lamp  flame,  or  hold  over  a  low,  direct  flame. 
Do  not  heat  too  rapidly.  The  heating  process  is  complete  when 
foaming  ceases  and  a  light-brown  color  appears,  and  should  not 
be  carried  beyond  this  stage. 

Allow  the  cup  and  contents  to  cool,  then  reweigh.  The  per- 
centage loss  in  weight  indicates  the  per  cent  of  moisture.  Most 
scales  read  this  direct. 


CHAPTER  XIX 

PREPARING  BUTTER  FOR  MARKET  AND  PREVENTION 

OF   MOLD 


In  the  preparation  of  butter  for  market,  care  should  be 
exercised  to  see  that  only  those  woods  which  will  not  affect  the 
flavor  of  the  butter  are  used  in  the  package.     From  practical 


-Elgin  style  butter- 
tub. 


Fig.  113. — Bradley 
butter-boxes. 


experience  and  from  various  experiments  it  has  been  found 
that  ash  and  spruce  are  the  most  suitable  woods  in  which  to  pack 
butter  to  be  delivered  to  the  market.  In  the  eastern  markets  a 
decided  preference  is  given  to  the  60-pound  ash  tub.  Prior  to 
the  use  of  this  tub  the  old-style  firkin  was  used.     Possibly  the 

294 


PREPARING  BUTTER  FOR  MARKET 


295 


reason  for  the  preference  given  to  the  6o-pound  tub  in  the  eastern 
market  lies  in  the  fact  that  many  dealers  have  so  arranged  their 
refrigerators  that  they  have  a  space  in  which  the  tub  fits.  Custom, 
based  upon  long  use  of  the  6o-pound  tub,  has  created  such  a 
decided  preference  for  butter  packed  in  this  manner  that  it 
will  sell  in  the  eastern  market  at  from  half  a  cent  to  one  cent 
more  a  pound  than  if  packed  in  a  cubical  box. 

The  Pacific  Coast  markets,  on  the  other  hand,  have  a  decided 


Fig.  114. — The  Eureka  hand 
butter-printer. 


Folded. 
Fig.  115.— Butter  cartons. 


preference  for  the  cubical  spruce  box,  and  will  pay  a  premium 
for  butter  packed  in  that  style. 

If  the  butter  is  to  be  cut  into  prints,  as  is  done  by  a 
great  many  dealers  at  the  present  time,  the  cubical  box  has  an 
advantage  over  the  tub.  Butter  so  packed  will  cut  into  prints 
with  less  waste. 

In  addition  to  spruce  for  the  cubical  box,  Southern  poplar 
has  been  used  quite  extensively.     A  box  of  the  following  dimen- 


296  PREPARING  BUTTER  FOR  MARKET 

sions  holds  65  pounds  of  butter,  and  has  given  excellent  satis- 
faction for  packing  butter  that  is  to  be  recut  into  prints.  The 
dimensions  are,  14I  by  13!  by  10^  inches,  A  inch  ends  and  sides, 
f  inch  top  and  bottom. 

For  the  Pacific  Coast  trade,  boxes  holding  as  much  as  90 
pounds  are  used  by  some  of  our  larger  creameries.  Boxes  of 
this  size  are  not  used  to  any  extent  in  the  eastern  markets. 

For  packing  butter  on  the  farm,  earthen  jars  give  excellent 
satisfaction,  particularly  if  they  are  well  glazed.  Due  to  the 
possibility  of  breakage,  such  jars  are  not  used  to  any  extent  for 
shipping  butter.  Earthern  jars  or  crocks  are  very  heavy  and 
easily  broken  during  transportation. 

For  shipping  in  small  packages  of  different  sizes,  the*  spruce 
package  is  most  commonly  used.  Some  tubs  manufactured  for 
this  purpose  hold  10,  20  and  30  pounds.  The  spruce  tub  is 
also  made  in  larger  sizes,  holding  from  60  to  65  pounds. 

While  spruce  will  not  flavor  butter  if  the  tub  is  rightly 
prepared,  the  disadvantage  of  the  spruce  package  is  that  it  soils 
very  easily  on  the  outside  and  gives  the  package  an  unsightly 
appearance. 

In  Canada,  New  Zealand  and  Australia  the  cubical  box  is 
used  exclusively.  These  boxes  are  made  to  hold  56  pounds  of 
butter.     Sometimes  double  covers  are  used. 

Storing  Butter  in  Creameries. — The  temperature  of  the  room 
in  which  butter  is  stored  should  be  as  low  as  conditions  will  per- 
mit. In  local  creameries  a  temperature  of  400  or  lower  should 
be  maintained.  In  small  creameries  the  butter  is  usually  kept 
at  the  creamery  from  three  to  six  days.  In  some  sections  of  the 
country  railroads  carry  refrigeration  cars  weekly;  in  others  semi- 
weekly.  Hence,  it  is  necessary  to  store  butter  at  as  low  a  tem- 
perature as  possible  while  it  is  waiting  to  be  shipped.  The 
refrigerator  in  which  the  butter  is  kept  at  the  creamery  should  be 
as  pure  and  dry  as  possible.  Damp  places  are  favorable  to  the 
production  of  molds.  Neither  vegetables  nor  foods  of  other 
kinds  should  be  allowed  in  the  refrigerator  with  butter,  as  they 
are  likely  to  impart  foreign  flavors  to  it. 

All  large  creameries,  the  so-called  centralizers,  are  equipped 


COST  OF  MANUFACTURING   BUTTER 


297 


with  mechanical  refrigeration  for  cooling  purposes.  Hence, 
they  are  able  to  keep  the  storage  room  for  butter  at  any  tem- 
perature desired.  On  the  contrary,  many  of  the  small  creameries 
have  to  depend  exclusively  upon  ice  for  refrigerating  purposes. 


Fig.  116. — Tub-fasteners;  common  tins. 


In  cases  where  ice  is  not  available,  water  can  be  utilized  for  the 
purpose  of  cooling.  Water  in  the  creamery  can  be  forced  through 
galvanized  iron  tanks,  which  are  properly  placed  in  the  butter 
storage  room  or  refrigerator  so  as  to  allow  as  much  cooling  sur- 


L 


o 


¥ 


Fig.  117. — Tub-fasteners:  tin  and  tack  combined. 


face  in  the  butter  room  as  possible.  This  is  merely  a  makeshift 
for  ice  and  will  not  cool  the  room  so  effectively,  but  in  the  absence 
of  ice  this  is  better  than  no  cooling  at  all. 

Cost  of  Manufacturing  Butter. — This  will  depend  upon  the 


Fig.  118. — Tub-fasteners:  riveted. 


volume  of  cream  received  and  the  kind  of  packages  in  which  the 
butter  is  to  be  packed  for  market.  About  fifteen  years  ago  the 
Iowa  State  Dairy  Commissioner  investigated  this  question,  and 
found  the  cost  of  manufacturing  ranged  from  1.2  cents  to  6 
cents  per  pound.     The  creamery  where  the  cost  ran  up  to  6 


298 


PREPARING   BUTTER   FOR  MARKET 


cents  a  pound  only  produced  30,000  pounds  of  butter  per  year. 
The  lowest  cost  of  manufacturing  was  submitted  by  a  co-opera- 
tive creamery  making  nearly  half  a  million  pounds  of  butter 
from  whole  milk  exclusively.  The  approximate  average  cost  of 
making  butter  for  the  creameries  in  the  State  of  Iowa  at  that 
time  was  2\  cents  a  pound.  As  labor,  coal  and  all  material  used 
in  the  manufacture  of  butter  have  greatly  advanced,  the  cost  at 
the  present  time  in  the  small  creameries  will  exceed  the  above 
figures. 

In  a  medium-sized  central  plant  the  cost  should  not  exceed 

2  cents  a  pound.  This  does  not 
include  the  package.  It  includes 
the  cost  of  factory  supplies,  such 
as  salt,  butter-coloring,  milk  for 
starters,  power,  labor,  refrigeration, 
factory  incidentals,  factory  main- 
tenance and  depreciation.  The 
cost  of  package  will  depend    en- 


Fig.  119. — Friday  printer. 
(J.  G.  Cherry  Co.). 


Fig.  120. — Friday  box. 


tirely  upon  the  kind  of  package  used  and  the  labor  necessary  to 
pack.  If  the  package  used  is  the  60  or  65  pound  tub  or  cubical 
box,  the  cost  of  package  and  labor  involved  will  not  be  very 
great.  If  the  butter  is  to  be  put  up  in  fourth-pound  or  pound 
prints,  the  cost  will  be  much  greater.  At  the  present  time,  the 
authors  would  place  the  cost,  with  the  package  included,  at  3  to 
3§  cents  per  pound. 


COST  OF  MANUFACTURING  BUTTER 


299 


During  the  fall  and  winter,  many  creameries  where  the 
milk  supply  is  rather  low  print  all  their  butter.  Many  of  the 
commission  men  will  pay  a  premium  of  i  cent  a  pound  for  butter 


Fig.  121. — Miller  hydraulic  cutter  for  hard  and  frozen  butter.      (L.  C.  Sharp 

Mfg.  Co.). 

so  packed.  The  butter-maker  has  more  time  at  this  period 
and  should  take  advantage  of  it  to  put  his  butter  up  in  neatly 
packed  prints.     A  creamery  should  have  its  own  wrapper,  and 


Dead  Air  Space 


'mmmmmMmmmmmMMMmm///////////M////// 

Fig.  122. — Cross-section  of  a  sewage-disposal  tank.      (Wallace's  Farmer.) 

it  should  bear  the  name  of  the  manufacturer.  If  the  butter  is 
good,  it  will  take  but  a  short  time  for  the  consumer  to  become 
familiar  with  this  brand  and  a  demand  for  it  will  eventually  be 


300 


PREPARING  BUTTER  FOR  MARKET 


created.  It  is  essential,  however,  that  we  consider  the  cost  of 
printing  the  butter  and  the  loss  in  printing.  Some  little  waste  of 
butter  accompanies  the  printing  process.  Butter  to  be  printed 
nicely  should  be  firm  but  not  hard,  so  that  the  print  may  assume 
its  proper  shape.  Butter  should  be  worked  to  a  point  where  it  is 
free  from  loose  moisture;  otherwise,  the  loss  will  be  much  heavier 
in  printing. 

Treatment  of  Tubs  and  Boxes. — Investigations  were  made  by 
Rogers  !  of  the  different  treatments  of  tubs  for  the  prevention 


Fig.  123. — Septic  tank  for  creamery  sewage  disposal.  (By  Prof.  J.  Michels.) 
The  tank  should  be  located  in  the  ground  with  the  top  within  a  foot  or 
two  of  the  surface.  It  may  be  constructed  of  planks.  Brick,  stone,  or 
concrete  is  preferable  for  durability.  The  tank  should  be  built  air-tight 
except  in  two  places,  D  and  E. 


of  contamination  by  mold.     Comparison  was  made  of  the  fol- 
lowing methods: 

(1)  Soaking  the  tubs  overnight  in  cold  water. 

(2)  Boiling  five  minutes  in  a  saturated  brine  solution  and 
leaving  in  the  brine  overnight. 

(3)  Soaking  overnight  in  a  brine  containing  9  per  cent  of 
commercial  formalin  (which  is  a  40  per  cent  solution  of  formalde- 
hyde). 

(4)  Coating  the  tubs  on  the  inside  with  paraffin. 

(5)  Immersing  the  tubs  for  a  few  seconds  in  paraffin  at  a 
temperature  of  2500  to  2600  F. 

Rogers  comments  upon  the  table  giving  results  of  his  investi- 
gations and  makes  some  general  observations,  as  follows : 

1  Bulletin  89,  Bureau  of  Animal  Husbandry,  U.  S.  Dept.  of  Agriculture. 


TREATMENT  OF  TUBS  AND   BOXES 


301 


302  PREPARING  BUTTER  FOR  MARKET 

"  It  will  be  seen  from  this  table  that  all  of  the  untreated 
tubs  became  moldy.  Of  the  six  tubs  treated  with  hot  brine, 
one  was  badly  molded,  one  was  slightly  molded  and  one  had 
mold  on  the  outside.  Of  the  six  tubs  soaked  in  the  brine- 
formaldehyde  mixture,  one  was  badly  molded.  None  of  the 
tubs  coated  with  paraffin  showed  any  mold  whatever,  and  the 
same  was  true  of  those  dipped  in  paraffin. 

"  To  treat  tubs  by  the  brine-formaldehyde  method  or  the 
hot-brine  method  a  vat  should  be  made  large  enough  to  hold 
submerged  the  tubs  used  in  one  day.  The  cost  of  either  of  these 
two  methods  is  insignificant  as  the  bath  may  be  used  repeatedly. 
The  objections  to  these  two  methods,  in  addition  to  their  inef- 
ficiency, would  probably  be  found  in  the  discoloring  of  the  wood 
and,  with  the  hot  brine,  in  the  excessive  weight  and  swelling  of 
the  tub." 

Paraffining  of  Tubs. — From  the  investigations  made  it  would 
seem  that  the  most  efficient  method  of  treating  tubs  or  boxes 
for  the  prevention  of  mold  is  to  paraffin  them  on  the  inside. 

Before  tubs  are  paraffined  they  should  be  thoroughly 
steamed.  In  extreme  cases,  where  tubs  are  very  open,  it  may 
be  necessary  to  soak  them,  but  only  in  such  cases.  Whether 
soaked  or  not,  the  tubs  should  be  steamed  just  before  paraffining 
them.  This  swells  and  tightens  the  tub,  and  heats  the  wood  and 
opens  its  pores  so  that  the  paraffin  will  penetrate  it  sufficiently 
and  at  the  same  time  form  a  nice,  smooth  coating.  The  par- 
affin should  be  heated  to  a  temperature  of  about  2500  F.  If 
much  below  this  it  is  apt  to  cause  the  coating  to  be  thick  and 
patchy,  and  if  much  above  it  is  likely  to  soak  into  the  wood  and 
not  form  a  proper  coating.  The  easiest  way  to  heat  the  paraffin 
in  a  creamery  is  to  place  a  steam  coil  in  the  bottom  of  the 
paraffin  tank  with  a  valve  or  dripcock  on  it  to  allow  the  escape 
of  condensed  steam. 

Where  the  work  is  done  in  a  small  way,  the  paraffin  can  be 
applied  in  one  of  two  ways — either  by  means  of  a  brush  or  by 
pouring  some  paraffin  into  the  tub,  rotating  it  to  cover  the  whole 
surface  and  then  placing  it  mouth  downward  to  drain  the  sur- 
plus paraffin  from  it.     But  in  a  creamery  of  any  size  a  suitable 


PARAFFINING  TUBS  REDUCES  LOSS  FROM   SHRINKAGE     303 


apparatus  for  spraying  the  inside  of   the  tub  with  paraffin 
should  be  used. 

As  it  only  requires  about  3  ounces  of  paraffin  for  a  tub  -that 
holds  60  to  65  pounds  of  butter  the  cost  is  not  great,  and  the 
work  entailed  in  paraffining  is  no  greater  than  that  of  either  of 
the  other  treatments  mentioned. 

Paraffin  furnishes  no  food  for  molds;  if  there  be  any  mold 
organisms  on  the  wood 
they  will  probably  be  de- 
stroyed to  a  very  great 
extent,  if  not  entirely, 
either  by  the  hot  paraffin 
spray  or  through  the  ex- 
clusion of  the  air  which 
they  require  for  growth; 
and,  even  failing  this, 
the  coating  of  paraffin 
shuts  them  off  from  the 
parchment  paper  and  the 
butter.  Furthermore,  as 
paraffin  is  impervious  to 
water,  the  space  between  the  liner  and  the  tub  remains  rilled 
with  water  or  brine  which  excludes  the  air  and  retards  or  pre- 
vents the  development  of  any  molds  that  may  be  present. 

Paraffining  Tubs  Reduces  Loss  from  Shrinkage. — Another 
strong  inducement  to  paraffin  tubs  is  the  saving  in  shrinkage, 
due  to  the  prevention  of  the  escape  of  moisture.  In  an  experi- 
ment made  by  Rogers,  during  his  investigations,  he  found  the 
shrinkage,  during  a  period  of  eight  days  in  creamery  storage 
and  in  transit,  on  butter  packed  in  paraffined  tubs  and  in  tubs 
soaked  in  brine,  respectively,  to  be  as  follows: 


Fig.  125. — Tub  paraffiner.      (Creamery 
Package  Mfg.  Co.). 


Treatment  of  Tubs 

Number  of 
Tubs 

Weight  of  Butter 

(Pounds) 

Shrinkage 
Pounds 

When  Packed 

After  Eight 
Days 

Paraffined .... 

12 
12 

757  i 
766! 

756 
759 

if 

Soaked 

7f 

304  PREPARING  BUTTER  FOR  MARKET 

Thus  the  saving  in  shrinkage,  through  paraffining,  was 
6  pounds  on  12  tubs  or  half  a  pound  per  tub. 

With  unsoaked,  paraffined  tubs  the  tare  should  be  marked 
on  the  package.  Such  tubs  may  be  as  much  as  2  pounds  lighter 
than  soaked  tubs. 

Treatment  of  Parchment  Paper. — As  parchment  paper  is  a 
good  medium  for  the  growth  of  mold  organisms  and  may  harbor 
the  spores,  though  showing  no  growth  of  mold,  it  is  quite  as 
important  to  treat  it  as  to  treat  the  tubs  for  the  prevention  of 
mold.  One  method  of  treatment  for  parchment  paper  is  to 
soak  it  for  at  least  ten  minutes,  before  using,  in  a  saturated 
solution  of  brine  at  or  near  the  boiling  point.  Russell  and  Hast- 
ings x  say,  "  A  most  efficient  way  of  treating  paper,  either  for 
tub  liners  or  print  wrappers,  is  to  place  same  in  boiling  water  for 
a  few  minutes. "  As  formalin  is  very  destructive  of  mold, 
another  very  efficient  treatment  for  parchment  paper  is  to  soak 
it  in  cold  brine  or  water  containing  formalin. 

YEASTS  AND   MOLDS  IN  BUTTER 

Bacteria  are  not  the  only  micro-organisms  found  in  milk  and 
its  products.  There  are  also  yeasts  and  molds,  the  mold  most 
commonly  found  being  Oidium  (plural  Oidia)  lactis,  or  the 
ordinary  white  mold  which  frequently  appears  on  the  surface 
of  sour  milk  or  cream. 

What  may  be  desirable  in  connection  with  one  dairy  product 
may  be  the  reverse  with  regard  to  another.  For  instance, 
Freudenreich  and  Marchel  have'  shown  that  in  the  ripening  of 
certain  Swiss  and  Belgian  soft  cheeses  the  common  white  mold 
(Oidium  lactis)  plays  a  principal  part.  In  these  products  its 
presence  is  not  only  desirable  but  necessary. 

On  the  other  hand,  it  is  found  that  where  yeasts  and  molds 
are  present  to  any  considerable  extent  in  butter,  it  is  not  nearly 
so  likely  to  possess  good  keeping  qualities  as  if  they  were  not 
present,  even  though  its  flavor  when  made  be  quite  satisfactory. 
They  may  be  present  in  cream  in  quite  large  numbers,  when  it 

1  Dairy  Bacteriology. 


YEASTS  AND  MOLDS  IN  BUTTER  305 

arrives  at  the  creamery,  but  if  it  be  efficiently  pasteurized  and 
kept  from  subsequent  contamination,  the  mere  fact  of  their 
presence  in  the  raw  cream  does  not  mean  that  the  butter  made 
from  this  cream  will  be  either  defective  in  flavor,  when  made,  or 
lacking  in  keeping  quality. 

A  study,  by  Bouska  and  Brown,  of  a  large  number  of  pack- 
ages of  butter  placed  in  cold  storage  showed  that  the  number  of 
yeasts  and  molds  present  in  butter,  when  made,  is  a  fair  cri- 
terion from  which  to  judge  of  its  keeping  quality.  To  put  it 
in  another  way,  the  number  of  yeasts  and  molds  present  in 
butter,  as  it  comes  from  the  churn,  is  a  good  indication  as  to  the 
efficiency  of  pasteurization  and  the  subsequent  handling  of  the 
cream  to  prevent  re-contamination. 

The  laboratory  of  the  American  Association  of  Creamery 
Butter  Manufacturers  has,  for  a  number  of  years,  made  counts 
of  the  number  of  yeasts  and  molds  in  samples  of  butter  sent  in 
by  its  members,  for  this  purpose.  As  a  result  of  this  work,  and 
the  advice  and  assistance  given/many  of  the  creameries  have  so 
improved  their  methods  and  equipment  as  to  practically  elim- 
inate yeasts  and  molds  from  their  butter,  and  make  a  product 
possessing  good  flavor  when  fresh  and  good  keeping  qualities^ 

Where  the  number  of  yeasts  and  molds  in  butter  is  reduced 
to  ten  or  less  per  cubic  centimeter — colonies  counted  without  the 
aid  of  a  magnifying  glass — this  is  regarded  as  excellent  work; 
and  several  of  the  creameries  have  reached  this  stage  of  effi- 
ciency. A  strong  effort  should  be  made  by  every  creamery  to 
keep  the  number  of  yeasts  and  molds  as  low  as  possible,  that  is, 
to  thoroughly  pasteurize  the  cream  and  prevent  subsequent 
contamination. 

Whether  or  not  the  yeasts  and  molds  present  in  butter  are  a 
direct  cause  of  deterioration  is  not  definitely  known,  although 
there  are  reasons  for  believing  that  this  is  not  necessarily  so. 
Hastings  found  yeasts  to  be  present  in  butter  which  won  first 
prize  in  a  Wisconsin  educational  contest.  The  presence  in 
butter  of  yeasts  and  molds  in  large  numbers  usually  means  the 
presence  of  other  undesirable  organisms  in  the  cream,  due  to 
one  or  more  of  the  following  causes: 


306  PREPARING  BUTTER  FOR  MARKET 

(i)  Inefficient  pasteurization,  the  pasteurizing  temperature 
being  too  low  or  not  maintained  throughout  the  run,  or  some  of 
the  cream  at  the  beginning  or  end  of  a  run  not  being  pasteurized. 

(2)  Lack  of  thorough  cleansing  or  sterilizing  of  the  utensils 
and  conduits — pumps,  vats,  faucets,  pipes,  churns,  etc. 

(3)  The  use  of  a  defective  starter — one  that  has  become 
contaminated  with  yeasts,  molds  and  undesirable  bacteria. 
Once  this  occurs  it  will  propagate  itself  from  day  to  day  until 
there  is  a  change  of  mother-starter. 

It  must  be  remembered  that  although  the  pasteurizing  may 
be  thoroughly  done  its  good  effects  may  be  largely  nullified 
through  subsequent  contamination.  Hence  the  final  test  of 
the  efficiency  of  pasteurization,  in  creamery  work,  should  really 
be  the  freedom  of  the  butter  from  the  ferments  which  cannot 
fail  to  be  eliminated  by  proper  pasteurization,  and  the  processes 
that  should  accompany  it.  Another  test  of  the  thoroughness 
of  the  pasteurization  of  milk  or  cream  for  butter-making  pur- 
poses is  the  Storch  test,  which  is  outlined  in  the  chapter  on 
Pasteurization. 

MOLD  ON  BUTTER 

The  development  of  mold  on  butter  constitutes  a  defect  that 
causes  large  losses.  Mold  not  only  greatly  mars  the  appearance 
of  a  package  of  butter  but  affects  its  flavor  as  well.  It  develops 
not  only  on  the  outside  of  butter  but  along  the  surfaces  of  any 
crevices  or  pockets  there  may  be  and  works  its  way  into  the 
butter.  Upon  this  point  we  quote  Thorn  and  Shaw  of  the  U.  S. 
Department  of  Agriculture:1  "  In  closed  packages,  wet  or 
damp  cellars,  or  carelessly  packed  masses  with  cracks  or  fis- 
sures in  which  moisture  collects,  mold  may  seriously  injure  the 
appearance  of  butter  packages  or  actually  induce  great  changes 
in  the  butter  itself."     No  score  is  given  to  moldy  butter. 

As  to  the  character  of  butter  that  affords  the  most  favorable 
conditions  for  the  growth  and  development  of  mold  organisms, 
if  any  be  present,  these  same  authorities  say,  "  Excess  of  curd 

1 "  Moldiness  in  Butter,"  Journal  of  Agricultural  Research,  Vol.  Ill,  No.  4. 


MOLD  ON  BUTTER  307 

favors  mold  growth.  Well-washed  butter  is  less  subject  to 
mold.  Leaky  butter — butter  from  which  water  or  buttermilk 
exudes  and  collects  in  the  wrappings  or  the  container — fur- 
nishes the  best  conditions  for  the  beginning  of  mold  growth. 
From  these  wet  areas  colonies  may  spread  to  the  butter  itself." 
These  facts  point  to  the  necessity  of  churning  at  the  right  tem- 
perature, washing  the  butter  properly  with  water  at  the  right 
temperature  and  properly  working  it,  so  as  to  free  the  butter  of 
excess  of  curdy  matter  and  buttermilk  and  make  a  butter  that 
is  not  porous  but  close,  and  in  which  the  moisture  is  incorporated 
in  fine  particles  instead  of  larger  droplets.  They  also  show  the 
importance  of  packing  butter  closely  so  as  to  free  it  of  air  pockets 
and  fissures. 

Conditions  Favorable  to  the  Growth  of  Molds. — Like  all 
other  plants,  large  and  small,  molds  require  certain  conditions 
for  growth.  They  differ  from  ordinary  plants  in  that  they  do 
not  require  light  for  their  growth,  but  grow  rather  better  in  the 
absence  of  light.  They  require  suitable  food,  but  find  this  in  or 
on  almost  any  organic  matter,  animal  or  vegetable,  such  as 
bread,  meat,  leather,  cheese,  etc.  They  require  moisture,  and 
hence  develop  rapidly  in  damp  rooms  and  on  damp  surfaces. 
They  require  a  certain  amount  of  air  and  will  not  grow  in  the 
absence  of  it.  As  to  temperature,  while  they  develop  most 
rapidly  in  a  reasonably  warm  atmosphere,  many  of  them  can 
accommodate  themselves  to  a  wide  range  of  temperature. 

Discolorations. — The  colors  produced  by  molds  range  from 
such  light  colors  as  orange-yellow  to  such  dark  colors  as  green,  a 
smudged  or  smoke  color  and  black,  according  to  the  type  of  mold 
present. 

Propagation  of  Molds. — Molds  reproduce  themselves  by 
means  of  buds  (conidia)  and  spores,  and  these  float  so  freely 
in  the  air  that  practically  no  exposed  surface  is  entirely  free  of 
them,  and  all  they  need  for  development  is  the  suitable  condi- 
tions we  have  already  outlined. 

Sources  of  Mold  on  Butter. — The  two  most  common  sources 
of  mold  on  butter  are  the  tubs  or  boxes  in  which  it  is  packed 
and  the  parchment  paper.     Wood  that  is  green,  sappy  or  damp 


308          PREPARING  BUTTER  FOR  MARKET 

is  a  good  medium  for  the  growth  of  mold;  so  also  is  parchment 
paper,  particularly  if  it  be  at  all  damp.  Hence  the  tubs  should 
be  made  of  well-seasoned  wood  of  good  quality,  and  both  the 
tubs  and  the  parchment  paper  should  be  kept  in  a  clean,  dry 
place.  In  the  planing  of  the  tub  staves  the  planer  should  be 
sufficiently  sharp  to  insure  a  smooth  surface. 


CHAPTER  XX 

THE   COMPOSITION   OF   BUTTER  AND  FACTORS  THAT 
INFLUENCE   ITS   CONTROL 

Acts  and  Rulings  as  to  Composition  of  Butter. — We  have 
only  one  Federal  statute  that  deals  specifically  with  the  com- 
position of  butter,  and  this  applies  only  to  the  District  of 
Columbia.  This  Act  was  approved  March  2,  1895,  and  requires 
that  butter  must  contain  83  per  cent  of  milk-fat,  not  more  than 
1 2  per  cent  of  water  and  not  more  than  5  per  cent  of  salt. 

No  attempt  has  been  made  to  enforce  the  above  statute,  no 
doubt  due  to  the  fact  that  creameries  could  not  comply  with  the 
same  under  the  ordinary  methods  of  butter-making. 

Act  of  August  2,  1886,  defines  butter  as  follows: 

"  That  for  the  purpose  of  this  Act  the  word  l  butter  '  shall 
be  understood  to  mean  the  food  product  usually  known  as  butter, 
and  which  is  made  exclusively  from  milk  or  cream,  or  both, 
with  or  without  common  salt,  and  with  or  without  additional 
coloring  matter." 

Act  of  May  9,  1902,  known  as  the  " adulterated"  law,  reads 
as  follows:  "Adulterated  butter"  is  hereby  defined  to  mean  a 
grade  of  butter  produced  by  mixing,  reworking,  rechurning  in 
milk  or  cream,  refining,  or  in  any  way  producing  a  uniform, 
purified,  or  improved  product  from  different  lots  or  parcels  of 
melted  or  unmelted  butter  or  butter-fat,  in  which  any  acid, 
alkali,  chemical,  or  any  substance  whatever  is  introduced  or 
used  for  the  purpose  or  with  the  effect  of  deodorizing  or  remov- 
ing therefrom  rancidity,  or  any  butter-fat  with  which  there  is 
mixed  any  substance  foreign  to  butter  as  herein  defined,  with 
intent  or  effect  of  cheapening  in  cost  the  product  or  any  butter 
in  the  manufacture  or  manipulation  of  which  any  process  or 

309 


310 


COMPOSITION  OF  BUTTER 


material  is  used  with  intent  or  effect  of  causing  the  absorption 
of  abnormal  quantities  of  water,  milk,  or  cream;  that  "  process 
butter  "  or  "  renovated  butter  "  is  hereby  defined  to  mean 
butter  which  has  been  subjected  to  any  process  by  which  it  is 
melted,  clarified  or  refined  and  made  to  resemble  genuine  butter, 
always  excepting  '  adulterated  butter '  as  defined  by  this 
Act." 

The  ruling  made  by  the  Secretary  of  the  Treasury,  the  Sec- 
retary of  Agriculture  and  the  Secretary  of  Labor  fixes  the  legal 
standard  of  moisture  in  butter  as  15.99  per  cent.     According  to 

this  ruling,  butter  that  contains  16 
per  cent  would  be  classified  as  adul- 
terated butter.  No  allowance  is 
made  for  chemical  errors  in  testing. 
While  the  chemists  allow  .2  per  cent 
for  error,  the  Internal  Revenue,  in 
enforcing  this  ruling,  makes  no  such 
Ml     «v  allowance.      In    some    districts    the 

*i^  courts  have  sustained  the   Internal 

Revenue  Department;  in  other  dis- 
tricts they  have  not.  Some  judges 
have  ruled  that  the  Congress  of  the 
United  States  is  the  only  body  that 
has  the  power  to  fix  definite  stand- 
ards for  food  products.  No  doubt 
the  Act  of  May  9,  1902,  refers  to 
methods  that  were  used  at  that  time  for  the  purpose  of  incor- 
porating abnormal  quantities  of  water. 

Compounds  for  Increasing  Yield  of  Butter. — The  Internal 
Revenue  ruling  is  based  entirely  upon  the  "  adulterated  " 
act.  Prior  to  the  adoption  of  the  law  of  1902  no  attempt  was 
made  by  the  government  to  enforce  any  regulations  concerning 
the  manufacture  of  butter.  At  this  early  period  various  com- 
pounds were  used  for  increasing  the  yield  of  butter. 

In  1893  the  United  States  Department  of  Agriculture  pub- 
lished Farmer's  Bulletin  No.  12,  "  Nostrums  for  Increasing 
Yield  of  Butter,"  by  Dr.  H.  W.  Wiley,  Chief  of  the  Bureau  of 


Fig.  126. — Ice-crusher. 


NEED   FOR  REGULATIONS  311 

Chemistry.  The  analyses  published  in  this  bulletin  reveal  the 
fact  that  the  compounds  used  increased  the  yield  of  butter. 
Analyses  reported  by  Dr.  Wiley: 

Water  Fat  Ash  (Salt)  Casein 

49-55  45-45  *-34  3-3^> 

3J-93  67-3°  15  -°3 

In  1900  experiments  were  carried  on  by  Dr.  J.  B.  Weems 
and  Prof.  F.  W.  Bouska  at  the  Iowa  Experiment  Station. 
They  tested  out  a  number  of  compounds  for  increasing  the  yield 
of  butter  and  got  the  following  results: 

Water  Fat  Ash  (Salt)  Casein 

41.54  53-°4  2.46  2.96 

The  second  recipe  was  composed  of  the  following  ingredients : 

Alumnae  pot.  sul 4  ounces 

Gum  acacia  pure 1  ounce 

Sacc.  lact 2  ounces  2  drachms 

Pure  pepsin 5  grains 

Giving  butter  of  the  following  composition: 

Water  Fat  Casein  Ash  (Salt) 

49.64  41.46  5-c5  3.84 

In  addition  to  the  above,  samples  of  suspicious  butter  were 
sent  to  the  Station  from  a  Chicago  Commission  House,  which 
showed, 

Water  Fat  Casein  Ash 

59.61  21.31  II.72  7.36 

42.76  44.92  5.IO  7.22 

Need  for  Regulations. — From  the  above  it  would  seem  that 
there  was  a  necessity  for  some  definite  regulations  concerning 
the  standard  or  composition  of  butter.  Possibly  the  Internal 
Revenue  people,  in  endeavoring  to  enforce  their  ruling  of  15.99 
per  cent,  have  been  rather  exacting  in  some  cases  where  prosecu- 
tions have  been  made. 

In  many  cases,  where  the  butter  was  found  to  slightly  exceed 


312  COMPOSITION  OF  BUTTER 

the  limit  set  by  the  Internal  Revenue  Department,  creameries 
were  assessed  10  cents  a  pound  tax  on  the  butter,  $50.00  a 
month  license,  or  $600.00  a  year,  and  an  additional  50  per  cent 
for  not  taking  out  a  license.  In  some  of  these  cases  a  few  pounds 
of  butter  were  seized  from  a  churning.  Many  creameries  have 
paid  these  assessments  to  avoid  the  notoriety  of  going  into  the 
courts  and  defending  their  rights.  Not  only  did  the  creamery 
pay  the  above  tax,  but  the  dealer  in  butter  was  assessed  $480.00 
for  a  year's  license  for  handling  so-called  adulterated  butter. 
Creameries  cannot  sue  the  government  for  the  refund  of  this 
money.  The  only  way  they  can  get  into  the  courts  is  to  sue  the 
local  agent.  In  many"  cases  that  have  come  up  in  the  courts, 
expert  butter-makers  have  appeared  as  witnesses,  st>me  in 
behalf  of  the  government  and  some  in  behalf  of  the  creameries. 
Some  butter  experts  have  made  affidavits  that  the  composition 
of  butter  can  be  controlled  and  others  have  made  affidavits  that 
it  cannot  be  controlled.  This  diversity  of  opinion  among  so- 
called  experts  no  doubt  has  been  due  to  lack  of  experience  on 
the  part  of  some  of  the  men  testifying.  No  doubt  all  wit- 
nesses appearing  were  honest  in  the  testimony  given. 

Control  of  Moisture  in  Butter. — After  spending  over  thirty 
years  in  the  butter  business  in  various  capacities  and  conducting 
a  vast  amount  of  experimental  work  in  an  endeavor  to  control 
the  composition  of  butter  the  authors  are  convinced  that  the 
moisture-content  of  butter  cannot  be  completely  controlled  at 
all  times.  Extensive  investigational  work  was  carried  on  at  the 
Iowa  Experiment  Station  on  this  subject  from  1901  to  1903. 
The  object  of  this  work  was  not  to  incorporate  water  in  butter 
but  to  get  butter  to  run  uniform  in  composition  throughout  the 
year.  Prior  to  this  investigational  work  the  senior  author  had  a 
number  of  analyses  made  of  the  butter  produced  in  some  of  the 
best  creameries  during  the  entire  year.  In  this  investigation 
the  fat-content,  the  moisture-content  and  the  salt-content  were 
found  to  vary  greatly.  In  the  winter  months  the  moisture- 
content  might  be  as  low  as  10  per  cent,  and  in  the  summer 
months  as  high  as  17  per  cent.  These  creameries  were  not 
making  any  effort  to  control  the  composition  of  their  butter. 


CONTROL  OF  MOISTURE  IN  BUTTER  313 

They  had  their  cream  in  such  a  condition  that  it  would  churn  in 
about  forty-five  minutes  and  the  butter  granules  would  be  so 
firm  that  the  butter  could  be  worked  sufficiently  to  prevent 
mottles  and  leaky  butter. 
Butter  was  churned  nor- 
mally to  granules  about 
as  large  as  wheat.  A 
number  of  conditions  was 

responsible  for   this   wide 

...  .  Fig.  127. — Rubber  mop. 

variation  in  the  composi- 
tion  from   season  to  season,  such   as  washing  with    too   cold 
water  in  the  winter  months  and  churning  at  too  high  a  tem- 
perature in  the  summer  months. 

Feeding  cows  on  dry  feed  during  the  winter  months  has  an 
effect  upon  the  composition  of  fats.  There  are  more  of  the 
high-melting  fats  present;  consequently,  the  butter  has  a 
higher  melting  point. 

In  the  early  days  of  the  creamery  business  practically  all 
butter  was  worked  on  the  table  worker.  It  was  the  custom  of 
many  makers  to  work  their  butter  twice.  After  having  the 
salt  incorporated  they  would  set  it  in  the  cooler  for  three  or  four 
hours  or  leave  ic  until  the  next  day.  This  had  a  tendency 
to  make  butter  with  a  lower  moisture-content,  as  the  second 
working  would  invariably  start  a  fresh  flow  of  moisture  from 
the  butter. 

The  invention  of  the  combined  churn  and  other  modern 
creamery  machinery  enabled  the  butter-maker  more  easily  to 
control  the  composition  of  the  butter.  The  combined  churn 
has  been  a  great  benefit  to  the  creamery  industry.  It  keeps  the 
butter  in  a  more  sanitary  condition  and  prevents  flies  and  dirt 
from  coming  in  contact  with  it.  The  butter  can  be  worked  in 
one  working  so  that  it  will  be  free  from  mottles  and  in  a  con- 
dition to  be  packed  directly  in  sanitary  packages.  Hence  it  is 
not  surprising  that  the  combined  churn  is  being  universally 
adopted  throughout  the  dairy  world. 

It  is  only  reasonable  to  suppose  that  since  the  adoption  of 
the  combined  churn  the  moisture-content  of  butter  would  run 


314  COMPOSITION  OF  BUTTER 

somewhat  higher  than  under  the  old  method  of  working  on  the 
table  worker,  due  to  the  variation  of  temperature,  which  affected 
the  hardness  of  the  butter  when  it  received  its  second  working. 

Many  of  the  earlier  analyses  were  of  butter  that  had  been 
manufactured  under  the  earlier  conditions  outlined  here. 
Hence,  it  is  not  surprising  that  the  composition  varied  greatly. 

The  composition  of  butter  may  vary  greatly  in  different 
localities.  There  are  two  instances  that  have  come  under  the 
observation  of  one  of  the  authors;  these  will  be  designated  as 
Creamery  A  and  Creamery  B.  Both  creameries  were  located 
in  the  northern  part  of  Iowa. 

Creamery  A  in  the  latter  part  of  the  month  of  May,  1908, 
sent  word  to  the  Iowa  Experiment  Station  that  the^  were 
unable    to    keep    the    moisture-content    of  their  butter  below 

16  per  cent.  Hence,  they  naturally  feared  that  their  butter 
would  be  seized  by  the  Internal  Revenue  authorities,  and  that 
they  would  be  prosecuted  for  making  adulterated  butter.  They 
maintained  they  had  had  some  butter  experts  there  to  help  them 
out  but  that  they  had  failed  to  accomplish  the  desired  results. 

The  authorities  of  the  Iowa  Experiment  Station  sent  them  a 
graduate  of  the  school,  Mr.  C.  L,  Mitchel,  who  had  had  a  great 
deal  of  practical  experience  before  going  to  college.  He  found 
that  the  butter-maker  was  churning  at  as  low  a  temperature  as 
440  F.,  and  was  trying  every  method  that  he  knew  of  to  hold  the 
moisture  below  15.99  Per  cent,  the  limit  fixed  by  the  Internal 
Revenue  Department.  Mr.  Mitchel  churned  out  two  churnings 
at  the  same  temperature  and  got  a  moisture-content  of  between 

17  and  18  per  cent.  He  therefore  changed  his  methods  and 
raised  the  temperature  to  52  °  F.,  and  after  completing  his 
churning  worked  the  butter  through  the  rolls  several  times  to 
expel  a  portion  of  the  moisture  before  applying  the  salt.  This 
method  worked  out  very  successfully.  The  rolls  expelled  con- 
siderable moisture  before  the  salt  was  applied.  As  soon  as  the 
salt  was  applied  it  attracted  the  moisture  and  the  result  was 
that  sufficient  moisture  was  easily  expelled  from  the  butter  to 
enable  him  to  make  butter  that  contained  moisture  below  the 
required  standard.     This  method  is  now  practiced  in  some  of  the 


ANALYSES  OF  COMMERCIAL  BUTTER  315 

large  creameries,  especially  in  the  early  spring  months  when  the 
grass  is  inclined  to  be  slushy  and  wet.  Butter  of  this  character 
has  a  tendency,  however,  to  be  slightly  greasy  or  overworked.   1 

Creamery  B  was  situated  in  the  northwestern  part  of  the  state. 
Mr.  J.  C.  Joslyn,  who  is  generally  recognized  as  one  of  our  lead- 
ing butter  authorities,  had  charge  of  this  plant.  Prior  to  the 
experience  that  Mr.  Joslyn  had  with  this  high  moisture  he  was 
under  the  impression  that  if  any  butter  contained  more  than 
1 6  per  cent  moisture,  this  excess  moisture  was  intentionally 
worked  in  by  the  maker.  One  day,  however,  he  had  a  churning 
where  the  method  as  far  as  he  knew  was  similar  to  that  he  had 
been  pursuing  to  make  the  best  butter.  This  particular  churning 
of  butter,  upon  testing,  showed  a  moisture-content  of  18  per  cent. 
The  peculiar  thing  about  this  butter  was  that  the  moisture  was 
so  incorporated  that  he  was  unable  to  expel  it,  even  by  reworking 
the  butter.  The  authors  have  heard  of  only  a  few  instances  of 
this  kind.  The  only  way  whereby  Mr.  Joslyn  succeeded  in 
reducing  the  moisture  was  to  put  the  butter  in  a  cooler  for  two 
days  and  then  break  it  up  into  small  pieces  and  rework  it.  In 
this  way  he  was  able  to  reduce  the  moisture  below  the  point 
permitted  by  the  government  regulation. 

One  of  the  authors,  in  visiting  the  Experiment  Station  at 
Copenhagen,  was  informed  by  Dr.  Holmes,  Dr.  Storch's  first 
assistant,  that  they  had  found  in  their  educational  scoring 
contest  in  Denmark  a  few  firkins  of  butter  that  ran  as  high  as 
1 8  per  cent  moisture  and  were  perfect  in  body  and  general 
appearance.  They  were  unable  to  give  any  explanation  for  the 
occasional  production  of  a  churning  of  this  kind.  The  finding  of 
excessive  moisture  in  butter  is  not  a  new  experience  in  the  butter 
business. 

ANALYSES     OF     COMMERCIAL     BUTTER     PUBLISHED     BETWEEN 
THIRTY  AND   FORTY  YEARS  AGO 

Blyth  says: 

"  There  is  no  standard  followed  or  fixed  with  regard  to  the 
percentage  of  water.  In  those  cases  in  which  the  fat  is  below 
8o  per  cent,  the  deficiency  of  fat  is  usually  from  excess  of  water, 


316 


COMPOSITION  OF  BUTTER 


and  seeing  the  variable  quantity  of  water  found  in  butter,  it 
is  wisest  not  to  certify  on  the  grounds  of  water  alone  unless  there 
is  sufficient  to  lower  the  percentage  of  fat  below  80  per  cent. 

"  At  the  Bath  Police  Court  (January,  1879),  a  dairyman  had 
been  summoned  for  selling  butter,  the  proximate  analysis  of  which 
showed  a  considerable  addition  of  water.  An  appeal  to  the 
Somerset  House  elicited  the  following  certificate: 

"  We  hereby  certify  that  we  have  analyzed  the  butter  and 
declare  the  result  of  our  analysis  to  be  as  follows : 

Per  Cent 

Water 23 .  27 

Butter-fat 74 .  69 

Salt 7$ 

Curd 1 .  26 

"  The  result  of  our  analyses  of  numerous  samples  of  ordinary 
commercial  butter  obtained  from  different  parts  of  the  country, 
including  the  south  of  England,  shows  that  the  portion  of  water 
is  very  variable  and  that  it  occasionally  amounts  to  as  much  as 
19  per  cent." 

James  Bell  obtained,  for  117  samples  of  butter  collected  in 
various  parts  of  the  kingdom,  and  asserted  by  him  to  be  genuine, 
proportions  of  water  varying  from  4.15  to  20.75  Per  cent- 

Lewkowitsch  in  his  work  says : 

"  The  proportion  of  water  in  butter  should  not  exceed  16 
per  cent." 

He  gives  the  following  table  to  illustrate  the  amount  of 
water  present  in  butter  on  the  English  market : 


No.  of 

Samples 

Examined 

Samples  C 
Per  Cent 

From 
11  to  14 

ontaining 
of  Water 

From 
10  to  16 

Above 
16 

Observer 

English  and  foreign . 
English 

560 
143 
4i7 

83.8 
70.7 
88.2 

94.2 

85-4 
97.2 

•9 

•7 

1.0 

Vieth 

H.  D.  Richmond 

Foreign 

H.  D.  Richmond 

ANALYSES  OF  COMMERCIAL  BUTTER  317 

The  above  analyses  reveal  the  fact  that  the  moisture-content 
of  butter  was  as  high  and  as  variable  as  at  the  present  time. 
Even  at  that  early  date  Blyth  fixed  80  per  cent  as  the  minimum 
fat-content  for  butter.  The  composition  of  butter  in  the  early 
days  was  more  variable  than  it  is  at  the  present  time.  This  is 
to  be  expected  from  the  fact  that  more  efficient  machinery  and 
methods  are  now  used  for  controlling  the  temperatures,  and  that 
butter-makers  have  a  better  understanding  of  the  effect  of  tem- 
perature on  the  control  of  moisture.  Butter  made  at  the  present 
time  will  undoubtedly  compare  very  favorably  with  butter 
made  in  earlier  years. 

Standards  in  Different  Countries. — Most  of  the  European 
countries  have  limited  regulations  to  specifying  the  moisture- 
content  of  butter  rather  than  the  fat-content.  The  Inter- 
national Dairy  Congress  held  in  Brussels  in  19 10  passed  resolu- 
tions favoring  18  per  cent  moisture  as  the  maximum  amount. 
England  has  a  16  per  cent  moisture  regulation  for  butter,  and 
24  per  cent  for  blended  butter.  France  has  an  18  per  cent  regu- 
lation and  Belgium  an  18  per  cent  regulation  for  moisture. 
Denmark  has  a  16  per  cent  regulation  for  export  and  20  per  cent 
for  home  consumption.  Canada  has  a  16  per  cent  regulation. 
Germany  has  an  18  per  cent  regulation  for  moisture  for  unsalted 
butter;  for  salted  butter  her  standard  requires  80  per  cent  fat 
and  not  more  than  16  per  cent  moisture.  Italy  has  an  82  per 
cent  fat  regulation.  Queensland  has  a  16  per  cent  moisture  regu- 
lation and  80  per  cent  fat.  Victoria  has  an  80  per  cent  fat  and 
16  per  cent  moisture  regulation. 

Possibly  the  reason  that  some  of  the  European  countries  have 
adopted  a  moisture  rather  than  a  fat  standard  is  that  it  is  much 
easier  to  make  a  moisture  determination  than  a  fat  determina- 
tion, as  in  dealing  with  moisture  we  are  only  dealing  with  one 
agent,  and  with  the  fat  determination  we  have  three  agents 
to  deal  with,  the  salt,  casein  and  moisture.  A  16  per  cent 
moisture  and  an  80  per  cent  fat  standard  for  butter  would  be 
practically  the  same.  Taking  3  per  cent  for  salt  and  1  per  cent 
for  casein,  this  would  leave  80  per  cent  fat,  providing  the  moisture 
were  carried  to  the  limit,  which  is  not  a  wise  or  a  safe  proposition. 


318  COMPOSITION  OF  BUTTER 

The  consumer  in  purchasing  butter  buys  it  for  its  food  value 
or  fat-content.  Therefore,  it  is  only  reasonable  that  the  cream- 
erymen  should  be  willing  to  have  all  their  butter  contain  at 
least  80  per  cent  fat.  No  doubt  the  reason  so  many  of  the 
European  countries  have  recommended  a  high  moisture-content 
of  18  per  cent  is  that  they  use  less  salt  in  their  butter.  An  18 
per  cent  moisture,  according  to  their  methods  of  salting,  would 
be  about  the  same  as  16  per  cent  in  this  country. 

The  authors  are  very  much  in  favor  of  a  definite  standard 
for  butter,  the  minimum  fat-content  being  80  per  cent  and 
the  moisture-content  16  per  cent.  Some  tolerance  or  allow- 
ance seems  necessary,  as  butter  may  vary  in  moisture,  especially 
from  one  end  of  the  churn  to  the  other,  as  much  as  1  or  1^  per  cent. 

Factors  that  Aid  in  Moisture  Control. — The  two  principal 
factors  that  aid  in  the  control  of  moisture  in  butter  are  the  per 
cent  of  fat  in  the  cream  and  the  temperature  at  which  the  cream 
is  churned.  Where  the  fat  runs  uniform  and  the  cream  contains 
a  high  per  cent  of  fat,  the  moisture  can  be  controlled  quite 
accurately  by  observing  the  size  of  the  granule  and  controlling 
the  temperature  of  churning. 

Bulletin  No.  101  of  the  Iowa  Experiment  Station,  page  167, 
gives  the  results  of  some  churnings  made  by  the  senior  author  in  a 
demonstration  to  short-course  students  during  the  month  of 
January,  1908.  This  butter  was  worked  in  a  Victory  churn. 
The  cream  for  these  particular  churnings  was  separated  from 
whole  milk  by  the  Randall  Creamery  Company,  Randall,  Iowa, 
and  shipped  to  the  Iowa  Experiment  Station.  Upon  arrival 
the  cream  tested  from  42  to  45  per  cent.  After  reducing  with  a 
starter,  holding  the  cream  over  night  and  churning  the  next 
morning,  the  results  given  in  the  accompanying  table  were 
obtained. 

Butter  proper  contains,  besides  the  water,  fat,  protein  and 
curd,  a  small  amount  of  milk-sugar,  .35  per  cent,  and  ash  from 
.14  to  .16  per  cent.  A  butter-maker,  to  be  successful,  must 
study  his  conditions  from  day  to  day  and  from  week  to  week; 
otherwise,  during  a  rainy  season  when  the  grass  becomes  slushy, 
the  moisture-content  is  likely  to  vary  or  exceed  the  limit,  even 


FACTORS  THAT   AID   IN   MOISTURE   CONTROL 


319 


Date 

Churn 

Lbs.  of 
Cream 

Per 
Cent 
Test 

But- 
ter- 
Fat 

Churn 
Tem- 
pera- 
ture 

But- 
ter- 
milk 
Temp. 

Tem- 
pera- 
ture 
of 
Spray 

Rev. 

for 
Salt 

Amt. 

of 

Butter 

Per 
Cent 
Over 

run 

Per 
Cent 
Water 

Dec.   31 
Jan       3 
Jan.      6 
Jan.      7 
Jan.    10 

Vic. 
Vic. 
Vic. 
Vic. 
Vic. 

1283 
1343 
I43S 
1204 
910 

32. 5 
36. 5 
34-5 
335 
33 

412 
490 
495 
403 
300 

58 
58 
57 
57 
57 

59 
59 
58 
58 
58 

54 
S3 

54 
54 
58 

14 
13 
13 
13 
18 

5i8 
600 
609 
499 
375 

22 

22.5 

23 

23 

24 

15.8 
15.9 
153 
15.9 
15.7 

though  the  same  regulations  have  been  observed  as  at  other 
times.  Makers  have  been  heard  to  say  that  they  could  control 
the  moisture-content  of  butter  to  within  two  or  three  hundredths 
of  the  limit.  Serious  doubts  may  be  entertained  as  to  the  cor- 
rectness of  such  a  statement. 

Not  very  long  ago  a  butter-maker  called  at  the  office  of  the 
American  Association  of  Creamery  Butter  Manufacturers  and 
proclaimed  that  he  was  churning  in  such  a  way  that  his  moisture- 
content  would  not  vary  more  than  two  or  three  hundredths  of  a 
per  cent  from  day  to  day.  He  was  asked  to  send  a  sample  of  his 
butter  to  the  Association  laboratory,  and  it  was  found  to  have  a 
moisture-content  of  nearly  17  per  cent.  The  moisture  in  the 
samples  he  sent  in  varied  2  per  cent,  or  ranged  from  15  to  17 
per  cent. 

Different  methods  are  used  for  controlling  moisture.  Some 
make  a  moisture  test  when  the  working  of  the  butter  is  about 
half  finished.  If  it  is  found  that  the  butter  runs  low  in  moisture 
they  add  to  the  churn  the  amount  of  water  they  wish  to  incor- 
porate and  continue  working  until  the  butter  takes  up  the  water 
added  to  it  in  the  churn.  On  the  contrary,  if  they  find  the 
moisture  is  too  high  they  fasten  the  churn  door  so  that  moisture 
will  escape  and  continue  to  work  the  butter  until  it  contains  the 
right  per  cent  of  moisture. 

Other  companies  that  manufacture  enormous  quantities  of 
butter  never  work  butter  in  water.  They  endeavor  to  control 
the  moisture  entirely  through  their  methods  of  churning.  They 
are  not,  however,  trying  to  crowd  the  limit  in  moisture. 

With    thick  cream,  or  cream    containing  a  low  per  cent  of 


320  COMPOSITION  OF  BUTTER 

fat,  it  is  a  more  difficult  problem  approximately  to  control  the 
composition  of  butter.  Churning  cream  at  a  high  temperature 
will  invariably  result  in  a  high  moisture-content  and  will  also 
result  in  an  extreme  loss  of  fat  in  the  buttermilk. 

In  churning  cream  of  medium-high  fat-content,  it  is  advisable 
to  fill  the  churn  only  about  half  full,  to  churn  at  such  a  low  tem- 
perature that  the  butter  will  gather  in  about  forty-five  to  fifty 
minutes,  and  to  churn  the  butter  to  granules  about  as  large  as 
peas.  A  small  variation  in  the  components  of  butter  affects  the 
quality  very  little,  provided  the  butter  has  been  properly  made 
and  the  components  properly  incorporated.  In  the  same  cream- 
ery the  composition  of  butter  varies  according  to  the  season  of 
the  year,  from  day  to  day  or  even  from  churning  to  churning. 
According  to  the  present  methods  of  manufacturing,  water  and 
salt  are  the  components  most  likely  to  vary.  Casein  will  vary  very 
little  if  the  butter  is  efficiently  washed  and  churned  in  a  condi- 
tion in  which  it  will  gather  firm.  Normally,  casein  is  estimated 
at  i  per  cent,  occasionally  it  has  been  found  to  run  as  high  as 
4  per  cent.  It  rarely  exceeds  2  per  cent,  and  seldom  falls  as 
low  as  A  of  1  per  cent.  A  high  curd-content  will  show  itself  in 
the  butter  in  the  form  of  milky  brine  or  in  the  form  of  white 
specks.  If  there  is  less  than  2  per  cent  present,  the  brine  will 
not  be  affected. 

One  of  our  large  creameries  had  an  average  casein  con- 
tent of  .65  for  a  year.  This  was  due  to  their  method  of  washing 
their  butter  a  number  of  times.  An  excessive  amount  of  casein 
in  butter  is  supposed  to  affect  its  keeping  qualities. 

Curd  and  milk-sugar  are  incorporated  from  the  milk  into 
the  butter  during  the  churning.  In  the  manufacture  of  butter 
for  storage,  these  substances  should  be  excluded  from  the  butter 
as  thoroughly  as  possible.  Milk-sugar  and  albuminoids  consti- 
tute the  chief  foods  for  bacterial  growth.  As  deterioration  of 
butter  has  been  demonstrated  to  be  due  chiefly  to  the  action 
of  micro-organisms  it  becomes  essential  to  restrain  their  growth 
as  much  as  possible  by  excluding  the  food  necessary  for  their 
growth. 

The  average  salt-content  of  butter  is  about  2\  per  cent; 


FACTORS  THAT  AID   IN  MOISTURE  CONTROL  321 

it  may  vary  from  i  to  4  per  cent.  The  amount  of  salt  properly 
dissolved  in  butter  depends  upon  the  amount  of  water  present. 
The  first  important  step  in  controlling  the  salt-content  is  to4iave 
a  reasonable  control  of  the  water-content  of  the  butter.  If 
there  is  16  per  cent  of  water  present  in  butter  it  is  desirable  to 
incorporate  as  much  salt  as  the  water  will  dissolve  within  the 
time  usually  allotted  for  that  purpose.  This  amount  of  salt 
suits  most  of  the  American  butter  markets. 

The  authors  have  analyzed  commercial  butter  containing  as 
high  as  8  per  cent  salt,  the  major  portion  of  this  being  present  in 
an  undissolved  condition.  Such  butter  is  called  gritty  and  is 
objected  to  by  the  consumer.  Salt  acts  as  a  preservative  to  some 
extent  and  adds  flavor  to  butter  provided  it  is  in  good  condition. 
It  has  been  said  that  the  addition  of  salt  has  some  effect  upon  the 
body  of  butter. 

Richmond  asserts  that  salted  butter  loses  more  water  on 
standing  than  unsalted  butter.  Undoubtedly  this  is  due  to  the 
fact  that  the  salt  added  to  butter  has  an  affinity  for  water  and 
the  drops  of  water  in  salted  butter  are  much  larger;  conse- 
quently, unless  the  butter  is  thoroughly  worked  so  as  to  break 
up  the  drops  of  water  into  smaller  drops,  this  will  have  a  ten- 
dency to  cause  what  is  known  to  the  trade  as  leaky  butter.  It  is 
much  more  difficult  to  expel  moisture  from  unsalted  butter; 
consequently,  a  great  deal  of  unsalted  butter  has  been  seized  by 
the  Internal  Revenue  officials  due  to  the  fact  that  it  exceeded 
the  prescribed  moisture  limit  set  by  the  Internal  Revenue 
Department. 

Unsalted  butter,  if  exposed  to  medium-high  temperatures, 
deteriorates  quite  rapidly,  and  frequently  has  a  pronounced 
cheesy  flavor.  If  it  is  kept  at  an  extremely  low  temperature  it 
keeps  well  in  storage.  Creameries  have  been  known  to  put  up 
their  butter  in  an  unsalted  condition  in  the  summer  and  put  it 
down  to  zero  or  below;  in  the  winter  they  took  it  out,  salted 
it,  and  worked  it  up  in  prints  as  fresh  butter  for  their  winter 
trade. 

Excessive  moisture  in  butter  causes  it  to  become  dull  or 
iusterless  in  color.     Butter  that  has  a  very  dry  appearance  and  is 


322  COMPOSITION  OF  BUTTER 

dull  in  color  is  invariably  high  in  moisture.  Overworking  butter 
or  working  it  to  a  condition  where  an  additional  amount  of  air  is 
incorporated  not  only  affects  the  color  but  gives  the  butter,  when 
placed  in  storage,  a  tendency  to  deteriorate  quite  rapidly  and 
become  fishy. 

The  temperature  of  the  wash-water  has  a  bearing  upon  the 
quality  of  butter.  Water  that  is  too  high  in  temperature  has  a 
tendency  to  soften  the  granules  and  thus  cause  them  to  absorb 
an  excessive  amount  of  moisture.  When  the  temperature  of 
cream  is  too  high  for  churning,  an  excessive  amount  of  butter- 
milk is  incorporated  in  the  butter  and  the  latter  will  not  keep  well 
either  in  storage  or  out  of  storage.  The  more  butter  is  worked 
in  the  presence  of  water  the  more  water  it  will  take  up! 

Making  butter  from  pasteurized  cream  has  a  tendency  to 
cause  a  greater  loss  of  fat  in  the  buttermilk. 


CHAPTER  XXI 
DEFECTS  FOUND  IN  BUTTER 

SOME  OF  THE  CAUSES  AND  THEIR  PREVENTION 

In  the  scoring  of  butter,  45  points  are  allowed  for  flavor, 
25  for  body,  15  for  color,  10  for  salt  and  5  for  package.  This  is 
the  score  that  is  generally  recognized  in  this  country.  Some 
expert  judges  have  used  the  score  of  50  for  flavor,  in  which  case 
5  are  taken  off  for  body,  allowing  20  instead  of  25.  We  can, 
therefore,  see  that  flavor  is  the  most  important  factor  in  deter- 
mining the  quality  of  butter.  The  other  defects  found  in  butter 
are  mechanical  defects  caused  by  the  process  of  manufacturing. 
Undesirable  flavors  affect  the  selling  price  of  butter  more  than 
anything  else. 

Flat  or  Insipid  Flavor. — Butter  that  lacks  flavor  is  sometimes 
termed  by  judges  insipid,  or  flat.  Various  terms  are  used  in 
describing  the  flavor  of  butter.  For  good  butter,  such  terms 
are  used  as  rich,  creamy,  aromatic.  Butter  may  be  rich  in  flavor 
without  having  a  pronounced  aroma.  This  kind  of  butter  has 
a  pleasant  palate  flavor.  A  flat  or  insipid  taste  may  be  due  to 
several  causes,  such  as  excessive  washing  and  making  butter 
from  unripened  cream.  If  cream  is  pasteurized  and  a  large  per 
cent  of  good  starter  is  used,  the  flat  flavor,  above  described,  will 
be  overcome. 

Butter  made  from  cream  of  which  the  flavor  is  not  clean  will 
score  much  higher  if  it  is  unsalted.  For  this  reason,  many 
creameries  manufacture  their  second-grade  cream  into  butter 
without  the  use  of  salt  and  make  what  is  known  to  the  trade  as 
"  sweet  butter."  The  theory  was  advanced  some  years  ago,  by 
writers  on  butter,  that  heavy  salting  covered  up  many  defects. 
Various  investigations  have  demonstrated  that  this  is  not  true. 

323 


324  DEFECTS   FOUND  IN   BUTTER 

Heavy  salting  has  a  tendency  to  bring  out  the  latent  flavors. 
Butter  made  during  the  winter  months  is  usually  deficient  in 
flavor,  especially  where  the  cream  has  not  been  ripened.  Hence, 
flat-flavored  butter  is  more  prevalent  in  winter  than  during  the 
summer  months. 

Stable  Flavors. — Stale  and  stable  flavors  are  also  quite 
prevalent  during  the  winter  months.  Many  of  the  organisms 
that  gain  access  to  milk  and  cream  during  the  winter  months 
come  from  the  stables  and  are  putrefactive  organisms  that 
decompose  the  casein,  such  as  Proteus  vulgaris,  B.  subtilis  and 
B.  fluorescens.  These  organisms  are  usually  found  in  milk 
produced  in  stables  and  gain  entrance  from  many  sources, 
such  as  manure,  feed,  water,  dirty  utensils  and  the  afr;  it  is 
therefore  practically  impossible  to  exclude  them.  There  are 
also  a  number  of  other  organisms  that  decompose  the  casein. 
Keeping  milk  too  long  in  a  poorly  ventilated  cow-stable  has  a 
tendency  to  cause  it  to  take  up  flavors  by  absorption.  Where 
cows  are  milked  in  warm  basement  stables,  poorly  ventilated, 
undesirable  fermentation  is  apt  to  predominate  in  souring  the 
cream  without  the  use  of  a  starter.  Two  of  the  principal  causes, 
however,  of  poor  quality  in  cream  are  failure  thoroughly  to  wash 
and  scald  all  dairy  utensils  that  come  in  contact  with  milk  or 
cream,  especially  separators,  and  failure  quickly  to  cool  the 
cream  to  a  low  temperature  to  check  fermentation. 

Flavors  Acquired  by  Absorption. — The  most  common  of  these 
are  house  flavors,  cellar  flavors  and  vegetable  flavors.  These 
flavors  are  all  taken  up  by  absorption  by  the  cream.  While 
pasteurization  will  not  remove  all  these  flavors,  it  has  the  effect 
of  removing  some  of  them.  Pasteurization  to  a  high  tempera- 
ture, 1800  to  1850  F.  under  the  flash  method,  or  1700  F.  under  the 
holding  method,  and  the  use  of  a  good  starter,  will  improve  the 
flavor  of  butter  made  from  such  cream.  House,  cellar  and  food 
flavors  are  at  times  so  pronounced  in  butter  that  a  butter  judge 
can  give  a  very  accurate  account  of  where  the  cream  was  kept 
by  merely  examining  the  butter. 

Cheesy  Flavor. — Cheesy  flavor  is  a  defect  that  is  sometimes 
found  in  butter  of  low-scoring  quality  that  has  been  kept  for  a 


SOME  OF  THE   CAUSES  AND   THEIR  PREVENTION         325 

long  time  at  high  temperatures.  When  butter  is  deteriorating 
very  rapidly  in  quality  it  usually  reaches  the  stage  where  it  has  a 
pronounced  cheesy  flavor,  which  later  on  changes  to  what  might 
be  described  as  a  turpentine  flavor.  Butter  of  this  character  will 
usually  sell  in  the  markets  as  "  Seconds."  Cheesy  flavor  is  said 
to  be  due  to  decomposition  of  the  curdy  matter  in  butter. 

Sour  Flavor. — Sour  flavor  is  sometimes  caused  by  over- 
ripening  the  cream  at  the  creamery.  The  authors  have  seen  good 
cream  from  whole  milk  overripened  to  such  an  extent  that  it 
produced  sour-flavored  butter.  The  churning  of  cream  with 
high  acidity,  without  reducing  this  acidity,  will  produce  sour 
butter.  Butter  judges  sometimes  describe  a  sour,  disagree- 
able flavor  as  a  dish-rag  flavor,  because  the  odor  accom- 
panying it  is  very  much  like  that  given  off  by  an  unwashed  dish 
cloth.  The  use  of  unclean  cloths  for  cleansing  dairy  utensils 
usually  means  the  transmission  of  undesirable  flavors  to  milk 
and  cream.  For  washing  utensils  a  brush  is  much  preferable  to  a 
cloth. 

Some  creameries  that  are  producing  the  best  butter  from 
shipped  cream  have  a  set  rule  that  all  cream  cans  must  be  thor- 
oughly cleansed  and  sterilized  before  being  returned  to  patrons. 

Harding  and  Ayers  both  report  that  they  were  able  to  produce 
good  milk  in  stables  where  manure  was  plentiful,  and  cobwebs 
were  hanging  from  the  ceiling,  by  sterilizing  all  dairy  utensils 
that  came  in  contact  with  the  milk  or  cream. 

Eckles,  when  connected  with  the  Iowa  Experiment  Station, 
isolated  Bacillus  coli  aerogenes,  added  it  to  pasteurized  skim- 
milk  and  made  a  starter,  and  added  the  same  to  sweet  cream 
for  the  purpose  of  ripening  or  souring  it  to  determine  the  injurious 
effect  it  would  have  upon  the  flavor  of  butter.  The  quality  of 
the  butter  produced  was  not  seriously  affected  by  this  starter. 
One  of  the  authors  had  the  privilege  of  scoring  this  butter,  and,  in 
his  judgment,  it  was  good  commercial  butter,  though  not  as 
pronounced  in  flavor  as  butter  made  from  cream  ripened  by  a 
culture  starter. 

Faulty  Factory  Conditions. — Bad  flavors  found  in  milk,  cream 
and  butter  are  sometimes  due  to  conditions  prevailing  in  the 


326  DEFECTS   FOUND  IN  BUTTER 

factories,  such  as  unsanitary  pumps  and  leaky  cream  vats  or 
coils.  Unsanitary  pumps  have  been  the  means  of  transmitting 
many  undesirable  flavors  to  both  milk  and  cream. 

Ayers  states  that  he  has  investigated  the  causes  of  undesirable 
flavors  in  milk  at  milk  plants,  and  has  found  the  trouble  to  be  due 
in  some  cases  to  unsanitary  pumps.  An  instance  of  this  kind 
came  up  in  one  of  the  best  creameries  in  Iowa,  a  whole-milk 
plant  that  had  been  noted  for  the  excellent  quality  of  the  butter 
it  was  producing.  A  cut  of  several  cents  a  pound  in  the  price  of 
the  butter  had  been  made,  due  to  a  very  disagreeable  flavor  that 
it  had  shown.  The  maker,  who  was  above  the  average  in  intel- 
ligence, was  unable  to  locate  the  cause  of  the  peculiar  flavor  that 
was  developing  in  his  cream  and  butter.  He  asked  the  State 
Dairy  Commissioner  to  send  one  of  his  best  men  to  help  them 
locate  their  trouble.  The  state  inspector  examined  the  creamery 
and  found  everything  in  apparently  a  good  condition.  He 
weighed  the  milk  himself,  and  found  the  quality  of  the  milk 
received  was  exceptionally  good.  As  soon  as  the  pump  was 
started  and  the  milk  was  pumped  up  to  the  heating  tank  and 
from  there  passed  into  the  separator,  the  first  cream  passing 
from  the  separator  showed  the  peculiar  flavor  that  was  found 
in  the  butter.  From  this  it  was  concluded  that  the  trouble  was 
in  the  pump.  The  pump  was  taken  apart,  heated  in  the  furnace 
for  some  time  and  thoroughly  cleansed,  then  put  together  again. 
When  the  pump  and  separator  were  started  again,  the  cream  was 
fine.  The  maker's  trouble  was  that  he  had  not  been  in  the 
habit  of  taking  the  pump  apart  for  cleaning  but  had  merely 
pumped  water  through  it  and  steamed  it.  The  hot  steam  evi- 
dently condensed,  covering  up  undesirable  organisms  and  pro- 
tecting them  from  the  heat  of  the  steam.  From  this  will  be 
seen  the  importance  of  sanitary  pipes  and  the  use  of  a  pump 
that  can  be  thoroughly  cleansed  every  time  it  is  used,  for  either 
cream  or  milk. 

Leaky  vats  and  coils  in  creameries  are  sometimes  the  cause 
of  bad  flavors.  A  leaky  vat  will  produce  in  cream  a  pungent, 
disagreeable  flavor  that  is  somewhat  different  from  the  flavor 
produced  by  almost  anything  else,  and  this  will  be  transmitted 


SOME   OF   THE   CAUSES   AND   THEIR   PREVENTION         327 

to  the  butter.  One  of  the  authors,  when  scoring  educational 
butter,  stated  in  writing  to  one  of  the  exhibitors  that  the  butter 
had  a  peculiar  flavor  that  was  undoubtedly  caused  by  one  of  his 
cream  vats  leaking.  Upon  examination  he  found  this  to  be  the 
case. 

Feed  Flavors. — Some  feeds  have  a  pronounced  effect  upon 
the  flavor  of  cream  and  butter;  some  of  these  are  desirable  and 
others  undesirable.  The  flavor  of  turnip  tops  or  turnips  affects 
the  sale  of  butter;  but  its  effect  can  be  largely  overcome  if  these 
are  fed  after  milking.  Where  cows  have  access  to  leeks,  wild 
onions  or  garlic,  very  undesirable  flavors  will  be  produced  in 
milk,  cream  and  butter.  Garlic  and  wild  onions  produce  such  a 
disagreeable,  pungent  flavor  in  butter  that  some  creameries 
have  refused  to  buy  cream  so  flavored,  while  other  creameries 
make  a  difference  of  10  cents  a  pound  in  the  price  of  the  milk-fat. 

Ayers  and  Johnson,  in  Farmer's  Bulletin  No.  610,  give  the 
results  of  their  investigation  on  this  subject. 

For  the  Removal  of  Garlic  or  Onion  Flavors. — It  is  a  well- 
known  fact  that  heating  milk  or  cream  to  a  high  temperature 
will  eliminate,  in  whole  or  in  part,  flavors  of  a  volatile  nature.  If 
we  combine  with  this  the  aeration  of  cream,  through  forcing  or 
blowing  air  into  it  under  pressure,  this  will  further  aid  in  the 
removal  of  such  flavors. 

In  Farmer's  Bulletin  608  of  the  U.  S.  Department  of  Agri- 
culture is  given  an  outline  of  an  experiment  for  the  removal  of 
onion  or  garlic  flavor.  In  this  experiment  a  vertical,  cylinder- 
shaped,  jacketed  tank,  with  an  agitator  in  it,  was  used  for  hold- 
ing and  heating  the  milk  or  cream,  and  above  this  was  placed  a 
smaller  tank  with  a  perforated  bottom.  The  milk  or  cream  was 
heated,  the  temperature  being  maintained  at  145  °  F.  or  above. 
Air  was  then  blown  into  the  milk  or  cream  through  a  pipe 
extending  almost  to  the  bottom  of  the  tank;  and  at  the  same 
time  the  milk  or  cream  was  constantly  pumped  into  the  upper 
tank  with  the  perforated  bottom,  from  which  it  ran  back,  in 
fine  streams,  which  reduced  the  foam  on  the  top  of  the  milk  or 
cream  in  the  larger  tank. 

It  was  found  in  this  experiment  that  the  higher  the  tern- 


DEFECTS  FOUND  IN  BUTTER 


perature  to  which  the  milk  or  cream  was  heated  the  more  efficient 
was  the  process.  While  it  is  impractical  to  heat  milk,  for  domestic 
use,  above  145 °  F.,  cream  for  butter-making  can  be  heated  to  a 
much  higher  temperature.  Milk  or  cream  with  a  "  strong  " 
onion  flavor  was  used.  As  to  results,  the  onion  flavor  was 
removed  from  milk  held  at  a  temperature  of  145  °  F.  in  from 
thirty  to  sixty  minutes ;  while  the  flavor  was  wholly  removed  from 
cream,  held  at  a  temperature  of  1600  F.  in  forty  minutes. 

A  considerable  amount  of  investigational  work  has  been  done 
by  the  Extension  Department  of  the  Purdue  Station,  Indiana,  on 
the  eradication  of  wild  garlic.  We  quote  from  what  they  have 
to  say,  as  follows: 

"  To  Eradicate  Wild  Garlic  on  a  Large  Scale. — Break  the 
infested  land  late  in  the  fall,  plowing  to  such  a  depth  as  to  turn 
up  as  many  of  the  garlic  bulbs  as  possible.  Leave  in  this  con- 
dition through  the  winter.  Replow  the  field  very  early  in  the 
spring — not  later  than  the  tenth  of  April,  if  possible — disk  and 
harrow  at  least  a  couple  of  times  and  plant  to  some  summer  crop 
such  as  corn,  soy  beans,  cow-peas,  potatoes,  sorghum  or  millet. 
No  garlic  plants  or  very  few  will  appear  during  the  summer, 
but  they  will  start  their  growth  again  in  the  fall.  Remove  the 
crop  in  time  to  allow  another  breaking  late  in  the  fall.  Repeat 
as  outlined  for  the  first  year,  that  is,  break  the  field  in  the  fall 
and  again  early  in  the  spring  and  plant  to  summer  crop.  This 
process  continued  every  season  for  three  to  five  years  will  clean 
out  the  garlic  entirely. 

"  To  Eradicate  Wild  Garlic  on  a  Small  Scale. — Spray  the 
plants  about  the  middle  of  April  with  orchard  heating  oil.  The 
oil  destroys  the  plants  entirely.  More  garlic  may  come  up, 
however,  the  following  fall  or  spring  from  the  bulbs  which  had 
not  germinated  in  the  previous  season.  These  must  be  sprayed 
again.  The  treatment  may  have  to  be  repeated,  in  some  cases, 
even  in  the  third  year." 

The  surest  remedy  for  overcoming  these  defects  in  milk  and 
cream  is  to  keep  the  cows  in  pastures  where  the  said  obnoxious 
plants  do  not  grow.  Nitrate  of  potash,  common  saltpeter,  has 
been  used  quite  extensively  in  cheese  sections  of  the  country  in 


SOME   OF  THE   CAUSES  AND   THEIR    PREVENTION  329 

the  late  fall  months,  when  turnip  tops  or  turnips  were  fed,  for 
the  purpose  of  eliminating  or  removing  odors  from  milk  pro- 
duced by  cows  having  access  to  turnip  tops  or  turnips. 

For  butter-making,  the  German  government  permits  the 
addition  of  nitrate  of  potash  to  milk  or  cream  for  the  purpose  of 
removing  flavors  produced  by  the  cows  eating  beets  or  beet  tops. 
Onions  and  garlic  predominate  in  the  early  spring  and  soon  dis- 
appear. As  soon  as  the  grass  advances  to  such  an  extent  that  it 
supplies  the  wants  of  the  cows,  they  prefer  it  to  weeds  of  any  kind. 

Advance  in  Lactation,  Winter  Feeds  and  Stable  Conditions.— 
It  is  thought  by  many  that  the  advanced  period  of  lactation  has  a 
pronounced  detrimental  effect  on  the  flavor  of  butter.  Experi- 
ments conducted  at  the  Iowa  Experiment  Station  in  1896  (Bul- 
letin 33.  pages  606-609),  by  McKay  and  Eckles,  do  not  sub- 
stantiate this  theory.  In  the  various  tests  made  the  milk 
from  the  Experiment  Station  herd  was  used.  The  milk  of 
fifteen  cows,  which  averaged  an  advance  of  239  days  in  their 
lactation  period,  was  classed  as  stripper  milk;  while  the  milk 
of  seventeen  cows,  which  averaged  an  advance  of  107  days  in 
their  lactation  period,  was  classed  as  milk  from  fresh  cows. 
During  this  experiment  the  cows  were  on  good  blue  grass 
and  were  being  fed,  in  addition,  one-quarter  of  a  pound  of 
cottonseed  meal  at  the  beginning  of  the  period.  The  cotton- 
seed meal  was  gradually  increased,  until  at  the  end  of  the  experi- 
ment they  received  1  pound  each  per  day.  The  milking  was 
done  under  personal  supervision  so  that  no  error  might  be  made 
through  mixing  the  milk  from  the  two  lots.  After  being  milked 
and  strained  into  cans  the  milk  was  taken  directly  to  the  cream- 
ery. When  the  evening's  milk  was  taken  to  the  creamery  it  was 
aerated  and  put  in  an  ice-box  which  was  filled  nearly  to  the  top 
of  the  cans  with  ice  and  water.  This  kept  the  milk  in  good  con- 
dition until  the  next  morning,  when  the  evening's  milk  and  the 
morning's  milk  were  mixed  together  and  separated. 

The  milk  from  the  fresh  cows  was  separated  and  cared  for  in 
the  same  manner  as  that  from  the  strippers.  In  order  to  make  a 
closer  connection  between  flavors  a  starter  was  prepared  from  the 
mixed  milk  of  two  stripper  cows,  the  periods  of  lactation  of  which 


330  DEFECTS   FOUND  IN  BUTTER 

were  339  and  356  days.  The  skim-milk  from  the  stripper  milk 
was  permitted  to  sour  and  was  then  used  as  a  starter  for  souring 
or  ripening  the  cream  separated  from  the  stripper  milk.  The 
fresh  cow's  milk  used  for  a  starter  was  produced  by  a  cow  that 
had  been  thirty  days  in  lactation.  The  skim-milk  was  per- 
mitted to  sour  in  the  same  way  as  that  from  the  milk  of  stripper 
cows. 

Various  tests  were  made  of  the  butter  made  from  the  dif- 
ferent milks.  This  butter  was  scored  by  W.  S.  Moore,  who  was 
then  official  scorer  for  the  Elgin  Board  of  Trade,  and  knew 
nothing  of  the  nature  of  the  experiment.  The  tubs  of  butter 
were  all  scored  by  number,  and  received  practically  the  same 
score.  The  two  highest-scoring  lots  of  butter  scored  95;  one 
of  these  lots  was  made  from  the  stripper  milk  and  the  other 
from  fresh  cows'  milk. 

From  this  and  similar  experiments  reported  in  Bulletin  No.  32, 
Iowa  Experiment  Station,  it  would  seem  that  the  period  of  lac- 
tation has  little  or.no  effect  upon  the  flavor  of  butter,  that  is, 
when  the  milk  is  separated  by  centrifugal  force,  or  by  the  little 
hand  separator.  Under  the  gravity  system  there  may  be  some 
difference,  as  many  dairymen  claim  there  is.  A  possible  explana- 
tion is  that  the  fat-globules,  as  is  well  known,  are  smaller  in  the 
milk  of  cows  well  advanced  in  lactation,  and  when  cream  from 
such  milk  is  raised  by  the  gravity  process  more  time  is  required 
for  the  cream  to  rise  than  when  the  milk  is  from  fresh  cows 
whose  milk  contains  fat-globules  of  much  greater  size. 

A  bitter  flavor  is  frequently  found  in  milk  or  cream  that  is 
kept  for  a  long  time  at  a  low  temperature.  There  seems  to  be 
present  in  almost  all  milk  an  organism  that  is  able  to  produce  a 
bitter  flavor  in. milk  or  cream  at  low  temperatures,  which  are 
unfavorable  to  the  development  of  the  lactic  acid  organisms. 
Hence,  the  defects  attributed  to  the  period  of  lactation  of  the  cow 
may  be  due  to  the  method  of  separating  the  cream. 

It  is  the  aim  of  almost  all  farmers  to  have  their  cows  come  in 
fresh  in  the  spring.  Therefore,  during  the  early  winter  months 
most  of  the  cows  are  well  advanced  in  their  period  of  lactation. 
At  this  time  they  are  milked  in  the  stables  and  fed  on  dry  feed, 


SOME  OF  THE  CAUSES  AND  THEIR  PREVENTION         331 

hence,  the  opportunity  for  the  milk  to  become  inoculated  with 
undesirable  organisms  is  very  great.  Such  conditions  are  apt 
to  create  in  the  minds  of  some  the  wrong  impression  thaf~the 
defects  found  under  winter  conditions  are  caused  by  the  advanced 
stage  of  lactation. 

Most  butter  manufactured  in  the  winter  has  what  butter 
judges  and  dealers  term  winter  flavors.  Where  the  milk  is 
received  sweet  at  the  creameries  and  the  cream  is  separated  and 
pasteurized  and  a  good  starter  is  used,  winter  conditions  can  be 
overcome.  The  importance  of  pasteurization  and  the  use  of  a 
good  starter  during  the  winter  months  cannot  be  emphasized 
too  strongly. 

A  quotation  from  Bulletin  101,  Iowa  Experiment  Station, 
page  167,  will  help  to  show  the  improvement  that  can  be  made 
in  the  flavor  of  butter  under  right  methods.  "  During  the  spe- 
cial winter  course,  beginning  the  latter  part  of  December,  1907, 
and  continuing  until  January,  1908,  the  Dairy  Department  of 
the  Iowa  Experiment  Station  arranged  with  the  Randall  Cream- 
ery Company,  Randall,  Iowa,  to  purchase  their  cream  to  be  used 
during  the  special  short-course."  In  this  case  it  is  presumed  that 
the  cows  were  well  advanced  in  the  period  of  lactation,  they  were 
certainly  subject  to  normal  winter  conditions.  The  Randall 
Creamery,  which  is  a  whole-milk  creamery,  received  the  milk 
and  separated  it.  The  sweet  cream,  in  this  case,  was  shipped  to 
the  Iowa  Experiment  Station  where  it  was  pasteurized,  ripened 
by  the  use  of  a  good  starter  and  churned  the  next  morning.  The 
cream  skimmed  at  the  plant  contained  42  to  45  per  cent  butter-fat, 
after  the  starter  was  added  it  contained  32  to  35  per  cent  fat. 
As  the  Randall  Creamery  Company  were  shipping  their  butter 
to  Gude  Bros.,  New  York,  they  made  a  request  that  the  butter 
produced  from  their  cream  at  the  Iowa  Experiment  Station  be 
shipped  to  the  same  place.  This  was  done,  with  instructions 
to  the  Gude  Bros,  and  P.  H.  Keiffer,  the  well-known  butter  judge 
of  that  firm,  to  score  each  shipment  critically  and  report  on  the 
same.  At  the  close  of  the  shipments,  Mr.  Keiffer  made  the 
following  report: 

"lam  very  much  pleased  to  be  able  to  report  that  the  butter 


332  DEFECTS  FOUND  IN  BUTTER 

which  you  shipped  us  this  winter,  made  from  cream  obtained 
from  the  Randall  Creamery  during  the  '  Short  Course,'  was  very 
fancy,  and  scored  from  93  to  96  points.  Very  little  butter 
arrived  at  that  time  as  fine  in  flavor  as  this.  Our  best  trade  was 
well  pleased  with  your  butter.  I  wish  that  more  of  the  cream- 
eries were  making  this  high  quality  butter  at  the  time  of  year 
when  it  is  so  difficult  to  make  it.  The  workmanship  was  perfect 
in  every  respect,  so  far  as  I  could  see,  and  the  flavor  was  fine." 

If  the  above-mentioned  cream  had  been  permitted  to  sour 
naturally  the  chances  are  that  the  flavor  would  have  been  very 
inferior  instead  of  fine.  The  authors  have  found  the  best  tem- 
perature for  ripening  cream  during  the  winter  months  to  be  700 
to  74°  F. 

From  the  above  it  seems  that  the  flavor  of  the  butter  is  not 
injured  by  the  advance  in  the  lactation  period  of  the  cow  but 
rather  by  undesirable  fermentations  that  develop  in  the  cream  if 
permitted  to  sour  naturally,  especially  during  the  winter  months. 

Tallowy  Flavor. — Tallowy  flavor  is  sometimes  found  in  butter, 
usually  in  butter  that  has  been  kept  under  rather  unfavorable 
conditions.  Butter  of  this  character  has  a  taste  somewhat 
similar  to  that  of  old  tallow.  This  peculiar  flavor  is  more  apt  to 
develop  in  print  than  in  tub  butter.  It  occurs,  however,  in  tub 
butter  when  it  has  been  bored  a  number  of  times,  thus  bringing 
the  air  into  contact  with  the  inner  parts  of  it.  It  is  found  some- 
times in  print  butter  which  has  been  exposed  to  the  air  and 
light,  and  the  color  may  be  seriously  affected,  even  to  the  extent 
of  bleaching  the  surface  butter  white. 

The  cause  of  tallowy  flavor  in  butter  is  oxidation.  U.  S. 
Bulletin  84  shows  the  effect  of  air  on  the  quality  of  butter.  A 
number  of  cans  of  butter  were  put  up  by  Gray,  and  hermetically 
sealed.  Some  of  these  cans  were  packed  full,  some  about  three- 
quarters  full,  some  about  half  full,  and  the  butter  in  one  lot  was 
put  in  loosely  where  the  air  came  into  contact  with  it.  Thus, 
the  amount  of  butter  in  these  cans  was  so  varied  that  different- 
sized  air  spaces  were  left.  The  solidly  packed  butter  in  every 
instance  kept  the  best  in  storage.  The  butter  that  was  loosely 
packed  deteriorated  very  rapidly,   showing  a  tallowy  or  fishy 


SOME  OF  THE  CAUSES  AND  THEIR  PREVENTION         333 

flavor.     Mr.  Gray,  in  commenting  upon  this  butter,  makes  the 
following  statement: 

"  Comparing  the  average  scores  of  butter  in  full  cans  and~in~ 
partially  full  cans  it  will  be  noted  that  there  were  differences  of 
i  to  5  points  in  favor  of  the  full  cans.  It  does  not  seem  necessary 
to  take  up  these  differences  in  detail.  This  deterioration  was 
without  doubt  due  to  air  in  the  partially  full  cans.  Since  in 
packing  butter  in  cans  there  is  no  necessity  for  having  the  cans 
only  partially  full,  neither  is  this  economical,  the  writer  does  not 
hesitate  to  state  that  where  the  sealing  is  done  at  atmospheric 
pressure  the  cans  should  be  entirely  filled,  leaving  as  little  air 
space  as  possible.  This  principle  may  be  applied  to  packing 
butter  in  other  packages.  The  butter  should  be  packed  solidly, 
leaving  as  few  air  spaces  as  possible.  Air  having  a  deteriorating 
effect  on  the  keeping  of  storage  butter,  it  would  be  expected  that 
butter  stored  in  small  open  packages,  as  pound  prints,  would 
not  keep  so  well  as  butter  in  large  packages.  This  is  a  belief 
that  has  already  been  accepted  by  many." 

High-scoring  butter  that  has  been  bored  a  number  of  times  at 
conventions  or  butter  contests,  has  a  tendency  to  deteriorate  in 
quality  and  show  a  slight  tallowy  flavor.  One  of  the  authors 
has  had  the  opportunity  of  judging  butter  at  various  times  in 
almost  every  dairy  state  in  this  country,  and  in  some  of  the  foreign 
countries,  thus  being  afforded  a  wide  range  of  opportunity  for 
examining  prize-winning  tubs  or  packages  of  butter. 

The  impression  prevails  with  some  that  high-scoring  butter 
lacks  keeping  quality.  The  only  way  whereby  this  statement 
could  be  verified  would  be  to  place  a  tub  of  the  same  butter  in 
storage  and  leave  it  there  at  storage  temperature  for  six  or  seven 
months.  When  we  take  into  consideration  that  some  of  the 
best  butter  at  a  contest  is  bored  a  great  many  times  and  thus 
exposed  to  the  air.  it  would  be  difficult  to  determine  whether  the 
defect  in  the  butter  were  caused  by  high  ripening  or  by  excessive 
boring.  An  instance  of  excessive  boring  was  brought  to  the 
attention  of  the  authors  in  a  national  contest  that  was  held  at 
Milwaukee  some  years  ago,  where  both  authors  were  present 
acting  in  the  capacity  of  experts,  one  pointing  out  the  defects  in 


334  DEFECTS  FOUND  IN  BUTTER 

the  butter  and  the  other  writing  each  exhibitor  giving  suggestions 
as  to  the  possible  cause  of  the  defects  existing.  Three  well- 
known  judges  worked  in  this  contest,  one  from  Philadelphia, 
one  from  Boston  and  the  third  from  Chicago.  There  were 
between  seven  and  eight  hundred  entries  of  butter  exhibited. 
On  the  first  day's  scoring  the  judges  set  aside  a  tub  of  extra 
fine  butter  to  be  rescored.  The  butter  had  a  fine  aroma  and  a 
clean  palate  flavor.  It  had  what  the  authors  would  describe  as  a 
creamy,  pleasant  flavor.  The  quality  of  this  butter  was  such 
that  it  was  used  as  a  standard  by  which  to  gage  the  score  of  the 
other  tubs  of  butter  in  the  final  scoring.  It  is  the  custom  in  a 
large  contest  of  this  kind  for  the  judges  to  set  aside  all  butter 
that  will  score  as  high  as  95  points  out  of  a  possible  100.  This 
butter  is  placed  in  what  the  judges  term  the  "  shake-down." 
After  all  the  other  butter  is  scored,  the  judges  after  resting  for 
some  time  go  to  work  on  the  "  shake-down  "  with  a  view  to 
placing  the  highest  scores.  This  particular  tub  of  butter  was 
used  as  a  standard  by  which  to  fix  the  other  grades.  The  result 
was  that  this  butter  was  bored  possibly  twenty-five  or  thirty 
times.  When  the  judges  in  the  final  score  placed  this  tub  fourth, 
on  the  ground  that  it  was  showing  at  that  time  a  slight  tallowy 
flavor,  their  decision  caused  some  dissension  and  dissatisfaction. 
It  certainly  was  not  fair  to  this  exhibitor  to  have  his  butter  bored 
so  many  times,  and  the  authors  believe  that  the  repeated  boring 
of  a  tub  of  butter  in  a  contest  with  the  resulting  contact  with  the 
air  is  not  a  fair  test  of  its  keeping  qualities. 

The  bleaching  of  tallowy  butter  does  not  usually  occur  until 
it  has  been  held  for  some  time.  Tallowy  flavor  is  not  very 
frequently  found  in  butter  that  has  been  placed  in  cold  storage. 

Overworking  butter  to  the  extent  that  it  will  become  greasy 
in  appearance  and  taste  has  a  tendency  to  cause  tallowy  flavor. 
By  overworking  butter,  extra  air  is  incorporated.  Butter  that  is 
churned  in  such  condition  that  the  granules  will  gather  firm 
will  stand  an  extra  amount  of  working  without  any  effect  upon 
the  body.  If  cream  is  churned  immediately  after  reaching  churn- 
ing temperature,  before  the  fat  has  sufficient  time  to  be  thor- 
oughly chilled,  the  fat  has  a  tendency  to  gather  in  a  soft  condi- 


SOME  OF  THE  CAUSES  AND  THEIR  PREVENTION         335 

tion,  and  if  such  butter  is  worked  to  the  extent  of  avoiding  mot- 
tles and  thoroughly  incorporating  the  salt,  there  is  danger 
of  the  body  being  seriously  affected  and  the  butter  having  a 
greasy  or  lardy  taste. 

Butter  which  has  been  well  made  and  kept  away  from  the  light 
when  placed  in  storage  will  seldom,  if  ever,  show  a  tallowy  flavor. 

Metallic  Flavors. — A  heavy  loss  is  sustained  by  the  butter 
industry  every  year  through  metallic  and  fishy  flavors.  There 
does  not  seem  to  be  a  clear  understanding  between  some  butter 
judges  as  to  the  distinction  between  these  two  classes  of  flavors. 
Metallic  flavor  and  fishy  flavor  are  two  entirely  different  things. 

Metallic  flavor  shows  in  the  butter  as  soon  as  it  is  churned 
and  is  invariably  found  in  butter  made  from  extremely  sour 
cream,  while  fishy  flavor  develops  in  butter  on  standing.  What 
actually  causes  metallic  flavor  is  not  thoroughly  understood,  and 
various  causes  have  been  assigned  by  different  people.  Metallic 
butter  has  a  pungent  flavor,  characteristic  of  the  taste  of  metallic 
salts.  Many  people  are  of  the  opinion  that  cream  acquires  a 
metallic  flavor  by  being  shipped  in  rusty  cans  or  coming  in 
contact  with  vats  or  coils  from  which  a  portion  of  the  tin  has 
been  removed. 

Certain  creameries  have  reported  that  in  some  cases  the  first 
churning  from  a  vat  of  cream  is  free  from  metallic  flavor,  while 
this  flavor  is  present  in  the  second  churning  from  the  same  vat. 
This  would  seem  to  indicate  that  the  flavor  is  due  to  the  develop- 
ment of  some  undesirable  fermentation,  or  to  bacterial  action. 

The  peculiar  feature  about  metallic  flavor  is  that  it  is  a  sea- 
sonal condition;  it  comes  and  disappears.  Heat  seems  to  inten- 
sify it  or  make  it  more  pronounced.  The  authors  have  known 
creameries  that  were  troubled  with  metallic  flavor  which  dis- 
appeared when  they  discontinued  pasteurization.  Cream  coming 
in  contact  with  vats,  coils  or  cans  from  which  the  tin  has  been 
removed  may  develop  a  metallic  flavor  as  a  result  of  this.  How- 
ever, when  we  take  into  consideration  that  metallic  flavor  is  a 
seasonal  condition,  the  theory  of  rusty  cans  or  the  partial 
removal  of  tin  from  vats  or  coils  does  not  offer  a  complete  explan- 
ation, as  creamerymen  use  the  same  cans  and  vats  during  the 


336  DEFECTS  FOUND  IN  BUTTER 

entire  season.  If  the  trouble  were  wholly  due  to  the  removal  of 
the  tin  from  the  vats  or  coils,  it  would  continue  throughout  the 
year. 

Guthrie  reports  that  he  placed  157  samples  of  cream  in  sterile 
glass  bottles  and  inoculated  with  an  individual  species  of  bacteria, 
and  that  52  showed  metallic  flavor.  Naturally  the  creamery- 
men  will  be  more  interested  in  what  will  prevent  metallic  flavor 
than  what  causes  it. 

One  of  the  largest  creamery  companies  in  this  country 
which,  like  others,  was  formerly  troubled  with  metallic  flavor 
claims  it  has  not  had  any  difficulty  for  several  years,  due  to  the 
method  observed  in  manufacturing.  The  president  of  the  com- 
pany stated  to  one  of  the  authors  that  they  had  bicf  good-bye 
to  metallic  flavor  several  years  ago.  The  method  they  pursue 
is  neutralization  to  a  low  degree  of  acidity  and  thorough  cleanli- 
ness. If  metallic  flavor  makes  its  appearance  they  reduce  the 
acidity  to  .27  per  cent  before  pasteurization  and  then  again,  by 
adding  limewater,  reduce  the  acidity  to  .04  or  .05  per  cent,  and 
ripen  with  a  pure  culture.  In  addition  to  this,  they  thoroughly 
cleanse  all  pipes  and  faucets,  and  everything  else  with  which  the 
cream  comes  in  contact.  They  maintain  that  this  method  of 
procedure  has  entirely  eliminated  metallic  flavor  from  the 
butter  they  manufacture. 

Fishy  Flavor. — Fishy  flavor  causes  greater  losses  in  butter 
than  any  other  one  defect.  In  recent  years  a  great  many  so- 
called  discoveries  have  been  made  by  different  scientists  as  to  the 
actual  cause  of  fishy  flavor.  These  discoveries  have  been  inves- 
tigated and  disputed  by  other  scientists,  and  the  result  is  that 
fishy  flavor  is  still  with  us.  Butter  made  from  high-acid  cream 
will  invariably  go  fishy  if  placed  in  cold  storage  for  a  long  time,  or 
for  the  natural  storage  period. 

Prior  to  the  introduction  of  partial  neutralization  of  acidity 
in  cream,  butter  made  from  hand-separator  cream  containing  a 
high  per  cent  of  acid  invariably  turned  fishy  when  kept  in  storage 
for  any  length  of  time.  One  of  the  leading  dealers  in  Chicago 
stated  that  for  two  years  he  had  bought  butter  made  by  some  of 
the  large  creameries  from  sour  cream  the  acidity  of  which  had 


SOME  OF  THE  CAUSES  AND  THEIR  PREVENTION  337 

not  been  reduced,  and  that  in  almost  every  case  the  butter  was 
fishy  when  it  came  out  of  storage.  He  said  that  as  a  result  of 
this  he  had  made  up  his  mind  never  to  buy  any  butter  from  the" 
so-called  centralized  creameries.  The  same  firm  now  prefers  to 
buy  butter  for  storage  purposes  from  large  creameries  where  the 
acidity  of  the  cream  is  reduced  or  controlled. 

The  following  is  a  quotation  from  U.  S.  Bulletin  by  L.  A. 
Rogers,  S.  C.  Thompson  and  J.  R.  Keithley,  page  8: 

"  In  a  tabulation  of  the  examination  of  259  samples  of 
experimental  butter  from  cream  of  known  acidity,  of  137  sam- 
ples from  cream  having  an  acidity  below  0.3  per  cent,  only  2,  or 
1.5  per  cent,  were  marked  '  fishy,'  while  of  122  samples  having 
an  acidity  of  0.3  per  cent  or  over,  60,  or  49.2  per  cent,  were  fishy. 
However,  in  all  results  which  are  *  dependent  on  the  sense  of 
taste,  allowance  should  be  made  for  difference  of  opinion  and  in 
the  conception  of  the  flavor  associated  with  any  particular 
designation/ ' 

U.  S.  Department  of  Agriculture  Bulletin  84,  page  23,  1906, 
by  C.  E.  Gray  and  G.  L.  McKay,  entitled  "  The  Keeping  Qual- 
ities of  Butter  made  under  Different  Conditions  and  Stored  at 
Different  Temperatures,"  would  indicate  that  acid  has  a  pro- 
nounced effect  in  producing  fishy  flavor  in  butter  unless  the 
acidity  of  the  cream  has  been  reduced  by  partial  neutralization. 
In  this  investigation  part  of  the  butter  was  made  at  Topeka, 
Kansas,  from  sour  cream.  Other  lots  were  made  at  Monticello, 
Iowa,  from  sweet  or  whole-milk  cream.  The  butter  made  from 
sweet  cream  did  not  turn  fishy  in  storage,  while  practically  all 
the  butter  made  from  sour  cream  had  a  pronounced  fishy  flavor 
after  being  kept  in  storage  for  some  time. 

Fishy  flavor  may  be  prevented  with  certainty  by  making 
butter  from  pasteurized  sweet  cream.  Butter  made  from  pas- 
teurized sweet  cream  with  a  starter  added,  but  without  ripening, 
seldom  if  ever  becomes  fishy. 

Of  25  different  churnings  of  cream  made  at  Strawberry  Point, 
Iowa,  July,  1907  (Bulletin  10 1,  by  McKay  and  Bower,  page  164), 
8  were  made  from  unpasteurized  cream  and  17  from  pasteurized 
cream.     The  cream  was  ripened  in  all  cases  with  a  pure  culture 


338  DEFECTS  FOUND  IN  BUTTER 

starter,  average  acidity  developed  .68  per  cent.  A  tub  of  butter 
from  each  churning  was  stored  in  New  York  between  six  and 
seven  months,  and  came  out  of  storage  without  any  trace  of  a 
fishy  flavor.  The  butter  was  scored  when  entering  storage  and 
when  coming  out  by  P.  H.  Keiffer,  the  well-known  butter  judge. 
The  average  scores  on  flavor  were,  first  scoring  38.17,  second 
scoring  38.25.  The  butter  was  pronounced  by  the  expert 
scorer  as  being  some  of  the  finest  butter  he  had  ever  seen  come 
out  of  storage.  Two  56-pound  boxes  from  each  churning  were 
shipped  to  London,  Liverpool,  and  Manchester,  England,  where 
they  were  scored  by  experts  and  pronounced  unusually  fine. 
The  average  in  England,  on  flavor,  was  38.5.  The  Strawberry 
Point  Creamery  at  that  time  received  about  50,000  pounds  of 
milk  daily.  The  milk  was  all  inspected  before  being  taken  into 
the  creamery,  and  any  milk  that  was  sour  or  tainted  was  rejected. 
The  milk  was  all  separated  by  power  separators  and  the  cream 
skimmed  so  as  to  contain  a  high  per  cent  of  milk-fat.  The  high 
per  cent  of  acid  developed  in  this  case  apparently  had  no  effect 
upon  the  keeping  quality  and  did  not  produce  a  fishy  flavor. 
It  would,  therefore,  seem  that  the  quality  of  the  milk  or  cream 
used  in  the  manufacture  of  butter  is  somewhat  responsible  for 
its  going  fishy. 

The  Danish  butter,  which  has  gained  a  world-wide  reputa- 
tion, is  practically  all  made  from  whole  milk  delivered  at  the 
factories,  the  cream  being  ripened  with  a  culture  starter.  While 
cream  of  high  acid  has  a  tendency  to  go  fishy,  fishiness  cannot 
be  attributed  entirely  to  the  development  of  acid  in  cream.  At 
the  present  time  probably  90  per  cent  of  the  butter  produced  in 
this  country  is  produced  from  cream  separated  on  the  farms. 
The  washing  of  the  separators  and  other  dairy  utensils  is  entirely 
in  the  hands  of  the  producer.  It  is  only  reasonable  to  suppose 
that  some  of  the  patrons  of  almost  every  creamery  do  not  pursue 
sanitary  methods  in  the  care  of  their  separators  and  other  utensils 
that  come  in  contact  with  the  cream.  Such  cream  is  undoubt- 
edly inoculated  with  undesirable  organisms  before  it  reaches  the 
creamery,  and  if  an  attempt  is  made  to  ripen  or  develop  much 
acid  in  it,  other  changes  will  also  take  place.     To  make  butter 


SOME  OF  THE  CAUSES  AND  THEIR  PREVENTION  339 

possessing  good  keeping  qualities,  under  present  conditions,  it  is 
necessary  to  neutralize  when  the  cream  is  very  sour,  and  develop 
a  low  degree  of  acidity.  The  Dairy  Division  has  found  that- 
pasteurizing  cream  with  a  low  degree  of  acidity  and  churning  it 
sweet,  or  without  the  use  of  a  starter,  produces  a  butter  that  is 
entirely  free  from  fishy  flavor. 


CHAPTER  XXII 
JUDGING  AND  GRADING  BUTTER 

Butter  may  be  judged  from  a  commercial  and  from  an  indi- 
vidual standpoint.  Individual  judgments  of  the  same  butter 
may  vary  considerably.  It  is  important  that  the  judge  should 
become  familiar  with  the  quality  of  butter  as  required  by  our 
standard  markets,  and  then  judge  the  butter  according  to  the 
demands  of  the  mass  of  the  consumers,  rather  than  according 
to  personal  likes  and  dislikes.  In  order  to  become  a  good  butter- 
judge,  it  is  essential  that  the  senses  of  taste  and  smell  be  acute. 
Even  if  one's  taste  and  smell  are  keen  and  sensitive,  consider- 
able practice  or  experience  is  necessary.  Almost  any  one  can 
tell  a  good  sample  of  butter  from  a  very  poor  one,  but  when  it 
comes  to  differentiating  between  two  samples  which  are  nearly 
alike  in  quality,  skill  and  experience  are  required. 

The  chief  requirement  in  scoring  butter  is  to  become  thor- 
oughly familiar  with  the  ideal  flavor  of  butter;  then  by  repeated 
comparisons  of  different  samples  of  butter  with  this  ideal 
flavor,  one  will  soon  become  efficient  in  grading  the  butter. 

Standard  for  Judging. — In  America  the  distinct  qualities 
which  are  noticed  in  butter  are  designated  according  to  the 
basis  of  points  given  below.  It  will  be  noticed  that  different 
values  are  given  to  the  different  characteristics,  according  to  their 
relative  importance.  The  score-card  given  below  is  used  com- 
mercially, and  is  based  upon  ioo  as  the  perfect  score: 

Score  Card 

No Perfect  Score                       Remarks 

Flavor 45         

Body 25 

Color 15         

Salt 10         

Style _5  

Total 100 

Date Scored  by 

340 


MANNER  OF  JUDGING  341 


MANNER   OF  JUDGING 


Body. — After  the  trierful  of  butter  has  been  drawn  out,  the 
first  thing  to  notice  is  the  aroma,  and  the  body  or  texture  of  the 
butter.  The  butter  on  the  outside  should  be  examined  at  once 
before  it  is  affected  by  the  temperature  of  the  room.  Notice  its 
color,  whether  it  is  even  or  uneven,  low  or  high.  Determine  by 
the  appearance  of  the  butter  and  the  way  it  feels  to  the  palate 
whether  it  is  greasy,  tallowy,  spongy,  or  sticky.  The  amount 
and  condition  of  brine  should  also  be  noted.  These  character- 
istics and  their  causes  have  been  previously  discussed.  Stroke 
the  plug  of  butter  with  a  knife  to  observe  the  color  closer.  Squeeze 
it  with  the  thumb  to  ascertain  the  character  of  the  body.  The 
aroma  of  the  butter  should  also  be  noticed  in  connection  with 
scoring  the  butter  on  body  or  texture,  as  it  is  more  pro- 
nounced immediately  after  the  trierful  of  butter  has  been 
drawn. 

Flavor. — It  is  impossible  to  describe  all  the  different  flavors 
found  in  butter.  There  are  perhaps  as  many  distinct  butter 
flavors  as  there  are  shades  of  color.  However,  there  are  a  few 
flavors  which  stand  out  more  prominently  and  are  more  commonly 
met  with  than  any  of  the  others.  Good  butter  should  possess  a 
clean,  mild,  rich,  creamy  flavor,  and  should  have  a  delicate,  mild, 
pleasant  aroma.  Some  butter- judges,  especially  foreign  judges, 
allow  a  separate  number  of  points  for  aroma  of  butter  in  the  score- 
card.  This  has  been  suggested  in  the  United  States  also,  owing 
to  the  fact  that  butter  may  have  little  aroma  and  still  have  a  good 
flavor. 

Color. — The  color  should  be  bright  and  even.  When  a  plug 
of  butter  is  drawn  with  a  trier  and  is  held  up  to  the  light,  it 
should  not  be  cloudy  and  dense,  but  should  be  almost  trans- 
parent and  bright.  The  chief  fault  found  with  the  color  of 
butter  is  unevenness.  It  may  be  streaky  or  mottled,  or  it  may 
be  too  high  or  too  low.  The  shade  of  color  will  vary  according  to 
the  different  markets;  in  most  of  our  markets  a  straw  color  is 
preferred.  There  has  been  a  tendency  recently  to  recommend  a 
comparatively  light  shade  of  color  in  butter,     A  reddish  color 


342  JUDGING  AND  GRADING  OF  BUTTER 

should  be  guarded  against,  except  when  the  market  demands 
it.  If  too  much  color  is  added,  butter  will  assume  this  hue, 
which  is  undesirable. 

Salt. — The  amount  of  salt  likewise  depends  upon  the  market, 
and  unless  the  salt-content  is  extremely  high,  or  extremely  low, 
butter  should  not  be  criticized  on  account  of  the  amount  of  salt. 
The  chief  thing  to  consider  in  judging  butter  on  its  salt-content 
is  the  condition  of  the  salt.  Notice  whether  it  has  been  thor- 
oughly dissolved  and  evenly  distributed. 

Style. — The  style  is  the  appearance  of  the  butter  and  package. 
Whatever  the  shape  of  the  package,  the  chief  thing  to  consider 
is  whether  it  is  clean  and  neatly  finished. 

CLASSIFICATION— GRADES  AND   SCORES 

While  the  different  butter  markets  differ  more  or  less  as  to 
details,  in  their  classification  and  grading  of  butter,  they  corre- 
spond closely  when  it  comes  to  the  large  essentials.  As  the  New 
York  and  Chicago  markets  are  the  two  great  butter  markets  of 
the  United  States,  the  following  is  quoted  from  the  Rules  of  the 
New  York  and  Chicago  Mercantile  Exchanges,  respectively: 

New  York 

i.  Butter  shall  be  classified  as  Creamery,  Renovated,  Ladles, 
Packing  Stock  and  Grease  Butter. 

DEFINITIONS 

2.  Creamery. — Butter  offered  under  this  classification  shall 
have  been  made  in  a  creamery  from  cream  separated  at  the 
creamery  or  gathered  from  farmers. 

3.  Renovated. — Butter  offered  under  this  classification  shall 
be  such  as  is  made  by  melting  butter,  clarifying  the  fat  therefrom 
and  rechurning  the  same  with  fresh  milk,  cream  or  skim-milk,  or 
other  similar  process. 

4.  Ladles. — Butter  offered  under  this  classification  shall  be 
such  as  is  collected  in  rolls,  lumps,  or  in  whole  packages  and 
reworked  by  the  dealer  or  shipper. 


CLASSIFICATION— GRADES  AND   SCORES  343 

5.  Packing  Stock. — Butter  offered  under  this  classification 
shall  be  original  farm-made  butter  in  rolls,  lumps  or  otherwise, 
without  additional  moisture  or  salt. 

6.  Grease  butter  shall  comprise  all  classes  of  butter  grading 
below  thirds,  or  of  packing  stock  grading  below  No.  3  as  herein- 
after specified  free  from  adulteration. 

GRADES 

7.  Creamery,  renovated  and  ladles  shall  be  graded  as  extras, 
firsts,  seconds  and  thirds;  and  packing  stock  shall  be  graded  as 
No.  1,  No.  2  and  No.  3. 

DEFINITION   OF   GRADES 

8.  Grades  of  salted  butter  must  conform  to  the  following 
requirements : 

Extras 

9.  Shall  be  a  standard  grade  of  average  fancy  quality  in  the 
season  when  offered  under  the  various  classifications.  Ninety 
per  cent  shall  conform  to  the  following  standard;  the  balance 
shall  not  grade  below  firsts: 

Flavor. — Must  be  sweet,  fresh  and  clean  for  the  season  when 
offered  if  creamery,  or  sweet,  fresh  and  reasonably  clean  if  ren- 
ovated or  ladles. 

Body. — Must  be  firm  and  uniform. 

Color. — Not  higher  than  natural  grass,  nor  lighter  than  light 
straw,  but  should  not  be  streaked  or  mottled. 

Salt.—  Medium  salted. 

Package. — Sound,  good,  uniform  and  clean. 

Firsts 

10.  Shall  be  a  grade  next  below  extras  and  must  be  good  butter 
for  the  season  when  made  and  offered,  under  the  various  classi- 
fications. Ninety  per  cent  shall  conform  to  the  following  stand- 
ard; the  balance  shall  not  grade  below  seconds. 

Flavor. — Must  be  reasonably  sweet,   reasonably  clean  and 
fresh  if  creamery  or  renovated,  and  reasonably  sweet  if  ladles. 
Body. — Must  be  firm  and  fairly  uniform. 


344  JUDGING  AND  GRADING  OF  BUTTER 

Color. — Reasonably  uniform,  neither  very  high  nor  very  light. 
Salt. — May  be  reasonably  high,  light  or  medium. 
Package. — Sound,  good,  uniform  and  clean. 

Seconds 

ii.  Shall  be  a  grade  next  below  Firsts. 
Flavor. — Must  be  reasonably  good. 

Body. — If  Creamery,  must  be  solid  boring.     If  Ladles  or 
Renovated,  must  be  90  per  cent  solid  boring. 
Color. — Fairly  uniform,  but  may  be  mottled. 
Salt. — May  be  high,  medium  or  light. 
Package. — Good  and  uniform. 

Thirds 

12.  Shall  be  a  grade  below  Seconds  and  may  consist  of  pro- 
miscuous lots. 

Flavor. — May  be  off -flavored  and  strong  on  tops  and  sides. 

Body. — Not  required  to  draw  a  full  trier. 

Color. — May  be  irregular  or  mottled. 

Salt. — High,  light  or  irregular. 

Package. — Any  kind  of  package  mentioned  at  time  of  sale. 

13.  (For  grades  higher  than  Extras,  see  paragraph  No.  2b). 

No.  1  Packing  Stock 

14.  Shall  be  sweet  and  sound,  packed  in  large,  new  or  good 
uniform  second-hand  barrels,  having  a  wooden  head  in  each  end, 
or  in  new  tubs,  either  to  be  parchment  paper  lined.  Barrels  and 
tubs  to  be  packed  full. 

No.  2  Packing  Stock 

15.  Shall  be  reasonably  sweet  and  sound,  and  may  be  packed 
in  promiscuous  or  different  kinds  of  barrels,  tubs  or  tierces,  with- 
out being  parchment  paper  lined,  and  may  be  packed  in  either 
two-headed  or  cloth-covered  barrels. 

No.  3  Packing  Stock 

16.  Shall  be  a  grade  below  No.  2,  and  may  be  off-flavored,  or 
strong;  may  be  packed  in  any  kind  or  kinds  of  packages. 


CLASSIFICATION— GRADES  AND   SCORES  345 

17.  Charges  for  inspection  of  Packing  Stock  shall  be  the  same 
as  the  rules  call  for  on  other  grades. 

18.  Mold. — There  shall  be  no  grade  for  butter  that  shows 
mold. 

Scoring 

19.  Scoring. — The  standard  official  score  shall  be  as  follows 
and  shall  apply  to  Salted  Creamery  Butter  only: 

Points 

Flavor 45 

Body 25 

Color 15 

Salt 10 

Style 5 

100 

20.  Extra  Creamery  may  score  either  91,  92  or  93  points  at 
the  discretion  of  the  Butter  Committee,  who  shall  determine  the 
required  score  from  time  to  time  in  such  manner  that  it  shall 
represent  an  average  fancy  quality  in  the  season  when  offered. 
But  butter  scoring  more  than  required  for  Extras  shall  be  deliv- 
erable on  a  contract  for  Extras,  and  may  be  branded  as  such  at  the 
request  of  seller,  or  buyer.  Any  change  in  the  Standard  score 
required  for  Extras  shall,  after  authorization  by  the  Butter  Com- 
mittee, be  announced  by  the  caller  at  the  opening  of  the  next 
regular  call  and  posted  upon  the  bulletin  board  of  the  Exchange 
and  be  effective  twenty-four  hours  later. 

21.  The  minimum  score  of  Firsts  shall,  at  all  times,  be  4 
points  below  the  score  required  for  Extras. 

22.  The  minimum  score  of  Seconds  shall  be  5  points  below 
the  minimum  score  required  for  Firsts. 

23.  The  minimum  score  of  Thirds  shall  be  7  points  below  the 
minimum  score  required  for  Seconds. 

UNSALTED   CREAMERY 

Extras 

24.  Shall  be  a  standard  grade  of  average  fancy  quality  in  the 
season  when  offered  under  the  various  classifications.     Ninety 


346  JUDGING  AND   GRADING   OF  BUTTER 

per  cent  shall  conform  to  the  following  standard;  the  balance 
shall  not  grade  below  Firsts. 

Flavor. — Must  be  sweet,  fresh  and  clean  for  the  season  when 
offered. 

Body. — Must  be  firm  and  uniform. 

Color. — May  be  very  light  straw,  white,  or  natural  grass,  but 
must  not  be  streaked  or  mottled.  The  seller  must  specify  the 
color  at  time  of  sale. 

Package. — New,  uniform  and  clean. 

Firsts 

25.  Shall  be  a  grade  next  below  Extras  and  must  be  good 
butter  for  the  season  when  made  and  offered,  under  the  various 
classifications.  Ninety  per  cent  shall  conform  to  the  following 
standard;  the  balance  shall  not  grade  below  Seconds. 

Flavor. — Must  be  reasonably  sweet,  reasonably  clean  and 
fresh. 

Body. — Must  be  firm  and  fairly  uniform. 

Color. — May  be  very  light  straw,  white,  or  natural  grass,  but 
must  not  be  streaked  or  mottled.  The  seller  must  specify  the 
color  at  time  of  sale. 

Package. — Sound,  good,  uniform  and  clean. 

Seconds 

26.  Shall  be  a  grade  next  below  Firsts. 
Flavor. — Must  be  reasonably  good. 
Body. — Must  be  solid  boring. 

Color. — Fairly  uniform,  but  may  be  mottled. 
Package. — Good  and  uniform. 

Thirds 

27.  Shall  be  a  grade  below  Seconds  and  may  consist  of 
promiscuous  lots. 

Flavor. — May  be  off-flavored  and  strong  on  tops  and  sides. 

Body. — Not  required  to  draw  a  full  trier. 

Color.— May  be  irregular  or  mottled. 

Package. — Any  kind  of  package  mentioned  at  time  of  sale. 


CLASSIFICATION— GRADES  AND   SCORES  347 

Scoring 

Points 

Flavor 45. 

Body 25 

Color '. .  *. 20 

Style 10 

100 

SALES    UNDER   THE    CALL 

28.  Creamery  butter  salted  of  a  score  higher  than  required 
for  Extras  may  be  offered  and  bid  for  by  score.  The  score  of 
such  butter  may  be  considered  its  grade;  or  such  higher  scoring 
butter  may  be  delivered  on  a  contract  for  Extras.  This  grade 
of  butter,  above  "  Extras,"  is  commonly  designated  by  the  trade 
as  "  Specials." 

Chicago 

1.  Butter  shall  be  classified  as  Creamery,  Centralized  Cream- 
ery, Held  Butter,  Renovated,  Ladles,  Packing  Stock  and  Grease 
Butter. 

DEFINITIONS 

2.  Creamery. — Butter  offered  under  this  classification  must 
be  made  in  a  creamery,  the  cream  having  either  been  separated 
from  the  whole  milk  at  the  creamery  or  received  by  team  or 
motor  at  the  creamery  direct  from  the  farm. 

3.  Centralized  Creamery. — Butter  offered  under  this  classi- 
fication must  be  made  in  a  creamery.  The  cream  used  in  the 
manufacture  of  this  butter  may  be  gathered  direct  from  the 
farmer  or  shipped  in  from  individual  shippers  or  cream  stations. 

4.  Held  Butter. — Butter  offered  under  this  classification 
shall  be  butter  that  has  become  cold  storage  butter  by  virtue 
of  the  laws  of  the  United  States  or  of  the  state  in  which  such 
butter  is  sold. 

5.  Renovated. — Butter  offered  under  this  classification  shall 
be  such  as  is  made  by  melting  the  butter,  clarifying  the  fat 
therefrom  and  rechurning  the  same  with  fresh  milk,  cream,  skim- 
milk  or  other  similar  processes. 


348  JUDGING  AND   GRADING   OF  BUTTER 

6.  Ladles. — Butter  offered  under  this  classification  shall  be 
such  as  is  collected  in  rolls,  lumps  or  whole  packages  and  reworked 
or  rechurned,  resalted  or  recolored  by  the  dealer  or  shipper. 

7.  Packing  Stock. — Butter  offered  under  this  classification 
shall  be  original  butter  without  additional  moisture  or  salt  from 
creamery  or  dairy  (but  may  be  from  miscellaneous  sources), 
which  has  been  collected  in  any  quantity  and  packed  in  tubs, 
barrels  or  other  containers.  It  must  be  of  a  quality  fit  for 
human  consumption  as  food  and  free  from  adulteration. 

8.  Grease  Butter. — Butter  offered  under  this  classification 
shall  consist  of  all  grades  of  butter  below  thirds.  If  packing  stock, 
below  No.  3,  and  free  from  adulteration. 

GRADES 

9.  Creamery  and  Held  Creamery  shall  be  graded  Extras, 
Firsts,  Seconds  and  Thirds.  Centralized  Creamery  shall  be 
graded  Extras,  Standards,  Firsts,  Seconds  and  Thirds.  Reno- 
vated and  Ladles  as  Firsts  and  Seconds.  Packing  Stock  as 
No.  1,  No.  2,  and  No.  3. 

Scoring 

10.  The  standard  official  score  for  salted  butter  shall  be  as 
follows: 

Points 

Flavor 45 

Body 25 

Color 15 

Salt 10 

Style 5 

n.  The  standard  official  score  for  unsalted  creamery  butter 
shall  be  as  follows: 

Points 

Flavor 45 

Body 30 

Color 15 

Style 10 

12.  All  grades  of  butter  must  conform  to  the  following  require- 
ments: 


CLASSIFICATION— GRADES  AND   SCORES  349 

Extras 

13.  Shall  consist  of  the  best  grade  of  butter  in  the  season  when 
produced  and  must  score  92  points  or  better. 

Flavor  must  be  sweet,  fresh  and  clean  when  offered  as  fresh, 
and  sweet  and  clean  when  offered  as  Held  Creamery.  Body 
must  be  firm  and  of  good  texture.  Color  may  be  either  light 
straw  color,  medium  or  high,  but  must  be  uniform  and  neither 
streaked  nor  mottled.  Salt  may  be  defined  as  light,  medium  or 
high,  but  must  not  be  gritty.  Package,  new,  sound,  good,  uni- 
form and  clean. 

Standards 

14.  Standards  shall  be  a  grade  of  centralized  creamery  of 
average  fine  quality  in  the  season  when  offered,  scoring  90  points 
and  above.  Flavor  must  be  fresh  and  clean  if  fresh,  and  clean 
if  held.  Body  must  be  firm  and  of  good  texture.  Color  may  be 
either  light  straw  color,  medium  or  high,  but  must  be  uniform, 
neither  streaked  nor  mottled.  Salt  may  be  defined  as  light 
medium  or  high,  but  must  not  be  gritty.  Package,  new,  sound, 
good,  uniform  and  clean. 

Firsts 

15.  Shall  be  a  grade  just  below  Extras,  scoring  from  88  to 
(but  not  including)  92  points,  must  be  good  butter  for  the  season 
when  made  and  offered  under  this  classification. 

Flavor  must  be  reasonably  clean  and  fresh  if  Creamery, 
Centralized  Creamery  or  Renovated,  and  reasonably  clean  and 
reasonably  sweet  if  Held.  Body  must  be  firm  and  of  fairly  good 
texture.  Color  reasonably  uniform,  neither  very  high  nor  very 
light.  Salt  may  be  light  medium  or  high.  Package,  new,  sound, 
good,  uniform  and  clean.  If  Ladles,  must  be  90  per  cent  solid 
boring,  color  reasonably  uniform,  package  sound  and  clean. 

Seconds 

16.  Shall  be  a  grade  below  Firsts.  The  minimum  scoring  of 
Creamery  Seconds  shall  be  4  points  below  the  minimum  scoring 
required  for  Firsts  or  a  range  of  from  84  to  (but  not  including)  88. 

Flavor  must  be  fairly  good.     Body,  if  Creamery,  Centralized 


350  JUDGING   AND   GRADING  OF   BUTTER 

Creamery  or  Held,  must  be  solid  boring.  If  Renovated  or  Ladles, 
must  be  90  per  cent  solid  boring.  Color,  fairly  uniform,  but 
may  be  mottled.  Salt  may  be  light  medium  or  high.  Package, 
good  and  uniform. 

Thirds 

17.  Shall  be  a  grade  below  Seconds  and  may  consist  of  pro- 
miscuous lots.  The  minimum  scoring  for  Creamery  Thirds  shall 
be  5  points  below  the  minimum  scoring  for  Seconds,  or  a  range 
from  79  to  (but  not  including)  84  points. 

Flavor  may  be  off-flavored  and  strong  on  tops  and  sides,  more 
or  less  rancid.  Body  not  required  to  draw  a  full  trier.  Color 
may  be  irregular  or  mottled.  Salt  high,  light  or  irregular. 
Package,  any  kind  of  package  mentioned  at  delivery. 

No.  1  Packing  Stock 

18.  Shall  be  original  butter,  solid  boring,  sweet  and  sound, 
without  additional  moisture  or  salt,  free  from  mold,  normal  in  oil 
contents,  packed  in  barrels  or  in  tubs  or  boxes.  Where  in  bar- 
rels, parchment-lined  packages  are  preferred.  When  in  either 
tubs,  boxes  or  barrels,  same  should  be  packed  full. 

No.  2  Packing  Stock 

19.  Shall  be  original  butter,  85  per  cent  of  it  solid  boring,  the 
other  1 5  per  cent  fairly  solid  boring,  reasonably  sweet  and  sound 
for  the  grade  offered;  may  be  slightly  deficient  in  oil  contents, 
must  be  free  from  mold  and  may  be  packed  in  different  kinds  of 
barrels,  tierces,  pails  or  boxes  with  or  without  paper  lining. 

No.  3  Packing  Stock 

20.  Shall  be  a  grade  of  quality  just  below  No.  2  Packing 
Stock,  but  above  the  classification  of  Grease  Butter;  may  be 
packed  in  any  or  all  kinds  of  packages. 

EXPORT   BUTTER 

The  observations  of  the  authors  have  been  that  the  reputation 
of  the  American  butter  on  the  English  market  is  not  all  that  is 
desirable.     Some  American  butter  is  good  enough  to  sell  on  an 


EXPORT  BUTTER 


351 


equality  with  Danish  butter,  and  in  some  instances  it  is  palmed 
off  as  such.  Much  poor  butter,  however,  has  been  allowed  to 
go  to  the  English  market,  and  this  has  in  some  measure  ruined 
the  reputation  of  our  butter. 

Butter  for  export  purposes  should  be  of  the  very  best,  and 
made  in  such  a  way  as  to  insure  good  keeping  qualities. 


Fig.  128.— Shipping  Russian  Butter  from  Siberia.     (U.  S.  Govt.  Bui.) 

The  standing  of  the  different  kinds  of  butter,  as  observed 
on  the  English  market,  were  as  follows: 

(1)  Fresh  French  Rolls. 

(2)  Danish  Creamery. 

(3)  Irish  Creamery. 

(4)  New  Zealand. 

(5)  Canadian,    Australian,    Argentine,    United   States,    and 
Siberia. 


(1)  Danish. 

(2)  New  Zealand. 

(3)  Siberia. 


For  Storage  Purposes 


CHAPTER  XXIII 
COLD  STORAGE  AND  BUTTER  FOR  STORAGE  PURPOSES 

History  of  Cold  Storage. — From  early  pioneer  days  the  people 
had  a  knowledge  of  the  fact  that  by  placing  perishable  food 
products  where  the  temperature  was  low  they  could  keep  them 
much  better.  Many  of  the  early  settlers  discovered  that  there 
was  a  zone  about  6  to  10  feet  below  the  surface  of  the  ground 
where  the  temperature  was  low.  Hence  they  dug  holes  in  the 
ground  in  which  to  keep  various  kinds  of  food  products.  Later, 
ice  was  used  in  various  ways  to  lower  the  temperature.  It  was 
discovered  that  the  lower  the  temperature,  the  better  the  food 
products  would  hold  their  flavor. 

Refrigeration,  as  we  have  it  to-day,  is  the  result  of  a  gradual 
evolution  as  to  both  process  and  efficiency.  Cooling  by  means 
of  ice  was  practiced  by  the  ancients.  We  read  that  the  monarch, 
Nero,  had  ice-houses  built  in  Rome  for  the  storing  of  natural  ice. 
The  cooling  effect  obtained  through  dissolving  certain  salts  was 
recognized  and  made  use  of,  as  far  back  as  1762,  by  Fahrenheit, 
the  inventor  of  the  thermometer  that  bears  his  name.  Salt- 
and-ice  mixtures  have  been  used  for  many  years  for  refrigerating 
purposes,  including  the  making  of  ice-cream,  etc.  In  what  is 
known  as  the  "  Cooper  System  "  of  refrigeration,  ice  and  calcium 
chloride  are  used.  Under  this  system  the  temperature  of  a  well- 
constructed  refrigerator  can  be  maintained  at  200  F.,  or  below. 

About  1845,  Dr.  Gorrie  of  New  Orleans  invented  a  cold-air 
refrigerating  machine.  Under  his  system  the  air  is  compressed 
but  is  not  condensed  to  a  liquid;  hence  it  is  not  so  practical  as 
the  more  modern  systems.  At  one  time  it  was  used  extensively 
on  ships  on  account  of  the  absence  of  obnoxious  gases.  This 
system,  while  mechanical,  differs  from  those  here  classed  under 
that  head. 

352 


MECHANICAL  REFRIGERATION  353 

Mechanical  Refrigeration. — The  underlying  principle  of 
mechanical  refrigeration,  that  of  the  consumption  of  heat  in  the 
vaporization  of  a  liquid,  is  not  a  new  one.  In  the  hot  climates  of 
many  eastern  countries,  water  for  drinking  purposes  is  kept  in 
porous  earthen  vessels  so  that  the  wind  may  evaporate  the 
moisture  as  it  oozes  through  the  pores  of  the  vessel  and  so  cool 
the  water.  In  Arizona,  and  to  some  extent  in  Oklahoma,  the 
farmers  cool  their  cream  by  wrapping  the  cream  can  with  a 
suitable  cloth  which  acts  as  a  wick  to  carry  up  moisture  to  be 
evaporated  and,  in  so  doing,  absorbs  heat  from  the  cream  in 
the  can  or,  in  other  words,  cools  the  cream. 

A  more  refined  and  very  much  more  effective  application  of 
this  principle  of  cooling,  through  the  vaporization  of  a  liquid, 
is  made  under  the  modern  system  of  mechanical  refrigeration. 
Under  the  Compression  system,  which  is  explained  in  the  chap- 
ter entitled,  "  Cooling  Facilities  for  Creameries  "  the  two  sub- 
stances most  commonly  used  are  anhydrous  ammonia  and  car- 
bonic acid  gas.  Professor  Carl  Linde  of  Munich  invented  the  first 
ammonia  compression  machine  in  1873.  The  carbonic  acid 
machine,  also  compression,  and  copied  after  Linde's  designs, 
appeared  in  1880.  In  large  creameries  and  central  cold  storage 
houses  in  this  country,  ammonia  plants  are  much  more  common 
than  carbonic  acid  plants,  although  on  ships  the  latter  are  prob- 
ably in  more  general  use.  In  another  system  of  mechanical 
refrigeration,  what  is  known  as  the  Absorption  process  is  used. 
Under  this  system  two  substances  are  used,  one  of  which  remains 
a  liquid  and  absorbs  the  other  at  ordinary  temperatures.  One 
combination  is  that  of  sulphuric  acid  and  water,  and  another, 
water  and  ammonia. 

Benefits  of  Cold  Storage. — Mechanical  refrigeration  was  first 
introduced  into  the  United  States  about  1888.  Its  general  effect, 
however,  upon  the  storing  of  food  and  upon  the  market  was  not 
appreciably  felt  until  about  1902.  Cold  storage  is  of  great  bene- 
fit to  the  public  as  a  whole.  As  to  the  consuming  public,  it 
enables  them  to  get  perishable  food  products  held  over  in  many 
cases  from  the  time  of  high  production  to  the  time  of  scarcity, 
thus  establishing  a  greater  uniformity  of  price  throughout  the 


354       COLD  STORAGE  AND  BUTTER  FOR  STORAGE  PURPOSES 

year.  The  producer  of  perishable  products  is  also  benefited 
from  the  fact  that  he  gets  higher  prices  during  the  time  that  he 
has  his  largest  supply,  which  he  would  not  be  able  to  get  if  such 
products  could  not  be  carried  over. 

Prior  to  the  general  use  of  mechanical  refrigeration  for  cold 
storage  purposes,  various  food  products  sold  at  very  low  prices  at 
the  time  of  high  production.     This  was  particularly  true  of  butter. 

A.  R.  Loomis,  of  Ft.  Dodge,  Iowa,  told  one  of  the  authors 
that  at  this  early  period  he  was  able  to  buy  several  carloads  of 
creamery  butter,  whole-milk  goods,  at  1 1  cents  a  pound.  Certain 
seasons  of  the  year  are  now  designated  as  cold-storage  seasons. 

The  season  which  is  recognized  as  that  for  making  butter  for 
storage  purposes  is  the  period  extending  from  the  latter  part  of 
May  to  the  first  of  July.  This  is  regarded  as  the  storage  season, 
although  some  butter  is  stored  at  other  times  of  the  year  as  well. 
Practically  all  butter,  however,  is  stored  during  the  storage 
season,  for  two  reasons:  first,  there  is  more  butter  made  at  this 
period  than  at  any  other  time  of  the  year;  second,  the  grass  is  at 
its  best,  and  the  conditions  are  more  favorable  for  making  good 
butter  than  at  any  other  time.  During  this  period  cows  are 
usually  milked  outside  and  there  is  less  chance  for  contamination. 
Hence,  the  best  butter  of  the  year  is  supposed  to  be  made  at  this 
time. 

Cold  storage  brings  into  the  market  many  dealers  in  butter. 
They  are  willing  to  pay  good  prices  in  the  summer,  taking  chances 
on  making  a  reasonable  profit  during  the  fall  and  winter  months, 
but  in  this  they  are  sometimes  disappointed.  In  various  states 
laws  have  been  enacted  to  regulate  cold  storage  and  prevent  the 
possibility  of  any  individual  or  combination  of  individuals 
cornering  the  food  products  for  the  purpose  of  forcing  prices 
beyond  what  will  net  a  reasonable  profit. 

A  general  agitation  was  started  throughout  the  country  by 
women's  clubs  and  other  organizations  when  food  prices  were 
extremely  high.  The  impression  prevailed  among  many  that 
cold  storage  was  responsible  for  hoarding  or  cornering  of  food 
products,  but  investigations  by  the  Federal  Government  showed 
that  hoarding  was  not  the  cause  of  high  prices.     Nevertheless, 


COST  OF  STORAGE  355 

the  agitation  became  so  pronounced  that  both  the  Republican 
Party  and  Democratic  Party  had  planks  in  their  platforms  asking 
that  laws  be  passed  by  Congress  to  regulate  cold  storage  and  also- 
demanding  a  limitation  of  the  length  of  time  that  food  products 
should  be  held  in  storage,  with  requests  for  branding  the  same 
as  storage  products. 

Cold  storage  has  undoubtedly  been  of  greater  benefit  to  the 
farmer  than  to  anyone  else,  as  the  fruits  he  produces  as  well  as 
his  poultry,  meats  and  dairy  products  go  into  storage.  If  it 
were  not  for  the  fact  that  these  products  can  be  carried  over  from 
the  time  when  there  is  an  abundant  supply  to  the  time  of  scarcity, 
very  low  prices  would  be  paid  for  them.  According  to  the  design 
of  Nature,  milk,  cream  and  almost  all  other  products  can  be 
produced  more  cheaply  in  the  summer  when  grass  is  abundant, 
than  in  the  winter  months.  This  is  an  economic  problem  with 
the  producer.  There  is  no  extra  labor  involved  in  feeding  cattle 
during  the  period  when  they  are  on  pasture. 

Cost  of  Storage. — The  average  length  of  time  that  butter 
is  kept  in  storage  is  approximately  five  or  six  months.  Very 
little  of  the  butter  that  is  held  in  cold  storage  belongs  to  the 
owner  of  the  cold-storage  plant;  it  is  held  by  many  people 
distributed  over  a  wide  area.  The  cold-storage  owner  rents 
space  in  the  storage  plant  to  dealers  for  storing  their  products, 
and  he  might  be  termed  a  landlord  renting  out  space. 

The  charges  by  the  cold-storage  companies  for  the  storage  of 
butter  are  usually  about  one-fifth  of  a  cent  per  pound  for  the  first 
month  and  one-eighth  of  a  cent  per  pound  for  each  succeeding 
month.  To  this  must  be  added  insurance  charges  and  interest 
on  investment.  For  the  purpose  of  completing  the  data  for  an 
estimate,  it  will  be  assumed  that  the  average  price  of  butter  for 
storage  is  35  cents,  and  the  interest  rate  7  per  cent.  On  this  basis 
the  cost,  per  pound,  of  carrying  butter  in  storage  for  a  period 
of  six  months  would  be  approximately  as  follows: 

Storage  charges,  including  insurance 1    cent 

Interest  on  investment 1 J  cents 

Total 2\  cents 


356        COLD  STORAGE  AND  BUTTER  FOR  STORAGE  PURPOSES 

Varying  conditions,  as  length  of  time  in  storage,  storage  rates, 
price  of  butter  and  rate  of  interest,  would,  of  course,  modify  the 
above  estimate.  It  is  a  fair  assumption  to  make  that  the  cost  of 
carrying  butter  during  the  storage  season  will  be  from  2  to  2  J 
cents  a  pound. 

Should  Cold  Storage  Butter  be  Branded? — A  great  deal  of 
butter  is  kept  in  what  are  known  as  coolers  by  the  butter  dealers 
or  merchants.  Such  butter  is  termed  fresh  butter  until  it  is 
placed  in  cold  storage  plants.  There  is  a  bill  before  Congress 
at  the  present  time  which  would  require  all  butter  held  at  a  tem- 
perature below  450  to  be  classified  as  cold-storage  butter.  If 
such  a  bill  should  become  law  in  its  present  form,  all  butter  made 
in  the  creameries  would  be  classified  as  storage  butter  as  s6on  as  it 
is  churned,  as  all  creameries  use  coolers  for  keeping  their  butter 
until  it  is  shipped,  when  it  is  placed  in  refrigerator  cars  and 
shipped  to  the  dealer.  The  latter  may  either  place  it  in  cold 
storage  or  carry  it  in  his  cooler  from  two  weeks  to  sixty  days, 
depending  upon  market  conditions.  There  are  a  few  firms 
who  have  coolers  large  enough  to  store  two  cars  of  butter,  and 
they  can  control  the  temperature  of  the  said  coolers  to  almost  any 
desired  point. 

The  placing  of  a  brand  on  butter  of  this  character  would  be 
the  means  of  causing  the  butter  to  sell  for  several  cents  per  pound 
less,  due  to  the  prejudice  that  exists  in  the  minds  of  many  people 
against  cold-storage  goods  of  any  kind.  From  a  health  stand- 
point there  is  no  necessity  for  placing  a  brand  on  butter  or  cheese 
held  in  cold  storage,  for  the  reason  that  good  butter  will  keep 
for  a  very  long  time  without  undergoing  practically  any  change, 
if  held  below  zero  Fahrenheit. 

Dr.  Larson,  Chief  of  the  Dairy  Division,  reports  having 
examined  butter  that  was  kept  for  three  years  in  storage  and 
which  scored  as  high  as  92  points  when  taken  out.  Where  butter 
is  held  at  a  temperature  between  5  and  10  degrees  below  zero  there 
is  very  little  danger  of  any  change  taking  place  during  a  period  of 
nine  to  twelve  months,  especially  if  the  butter  is  good.  The 
authors  know  of  a  specific  case  in  Chicago,  where,  owing  to 
declining  prices  and  in  order  to  avoid  a  loss,  a  buyer  carried 


BUTTER  FOR  STORAGE  357 

butter  over  from  one  season  to  the  next.  This  butter  was  held  in 
storage  approximately  eighteen  months,  at  a  temperature  below 
zero,  and  when  taken  out  of  storage  it  showed  little  or  no  deterio1 
ration.  Holding  this  length  of  time  is,  of  course,  not  the  rule, 
as  most  of  the  butter  put  into  storage  is  not  held  over  six  months, 
or  at  most  nine  months. 

Butter  going  into  storage  and  butter  coming  out  of  storage 
are  both  sold  by  grade.  The  changes  that  take  place  in  storage 
butter  will  depend,  to  a  very  large  extent,  upon  the  condition  of 
the  butter  when  going  into  storage,  also  upon  the  material  from 
which  it  was  made  and  the  temperature  at  which  it  has  been  held. 
Butter  held  at  high  temperatures  deteriorates  quite  rapidly  and 
becomes  rancid  in  time. 

Butter  for  Storage. — One  of  the  most  common  defects  found 
in  butter  made  from  raw  cream  is  what  is  known  to  the  trade 
as  cheesy  or  fishy  flavor.  The  condition  of  the  material  used  has 
a  direct  bearing  upon  the  changes  that  take  place.  If  butter  is 
made  from  sweet  cream,  or  cream  nearly  sweet,  that  has  been 
efficiently  pasteurized,  there  is  very  little  danger  of  its  going 
fishy;  on  the  other  hand,  if  the  material  used  is  not  of  good 
quality,  the  chances  will  be  very  favorable  to  its  either  becoming 
fishy  or  showing  other  deterioration  defects  that  are  found  in  poor 
storage  butter. 

In  a  large  shipment  of  butter,  made  at  Strawberry  Point 
under  the  direction  of  one  of  the  authors,  the  cream  used  had 
been  efficiently  pasteurized  and  its  quality  was  all  that  could  be 
desired  in  the  way  of  flavor.  The  butter  was  held  in  New  York 
in  storage  for  between  six  and  seven  months.  The  average  score 
on  flavor,  when  entering  storage,  was  38.17,  and  on  body  24.88; 
when  coming  out  it  was,  flavor  38.25  and  body  24.92. 

The  condition  of  the  material  used  in  the  manufacture  of 
butter,  that  is,  the  milk  or  cream,  has  a  pronounced  bearing  upon 
the  quality  of  the  butter  when  it  comes  out  of  storage.  Butter 
made  from  cream  with  a  low  acid  and  light  salt  will  keep  in  storage 
better  than  butter  made  from  cream  with  a  high  acid,  especially 
if  the  acid  has  been  developed  in  the  cream  without  being  con- 
trolled by  the  manufacturer. 


358        COLD  STORAGE  AND  BUTTER  FOR  STORAGE  PURPOSES 

The  butter  referred  to  above,  which  was  made  at  Strawberry 
Point,  was  made  from  cream  containing  .68  of  i  per  cent  of  acid, 
and  it  was  ripened  with  a  pure  culture  starter;  it  must  be  taken 
into  consideration,  however,  that  Strawberry  Point  at  that  time 
received  whole  milk  of  an  exceptionally  good  quality.  The  milk 
was  inspected  on  the  stand  by  a  man  who  had  been  engaged  for 
that  purpose,  and  any  milk  that  was  sour  or  tainted  was  rejected. 
At  the  present  time  very  little  butter  is  made  under  what  is 
known  as  the  whole-milk  system.  Possibly  90  to  95  per  cent  of 
the  butter  produced  in  this  country  is  manufactured  from  so- 
called  hand-separator  cream.  The  result  is  that  the  producer 
has  entire  charge  of  cleansing  separators  and  other  utensils 
that  come  in  contact  with  milk  and  cream,  and  some  of  the 
producers  do  not  adopt  the  most  sanitary  methods  in  cleansing 
their  separators  and  other  utensils  used  in  the  dairy.  In  addi- 
tion to  this,  there  is,  in  many  cases,  the  neglect  to  properly  cool 
the  cream  after  each  separation.  Some  make  a  practice  of  mixing 
the  warm  cream  with  the  previous  lot  that  was  separated  without 
cooling,  and  the  cream  may  also  be  held  for  a  long  time  on  the 
farm  before  it  is  delivered  to  the  creamery  or  cream-buying 
station. 

To  the  farmer  the  delivery  of  cream  involves  an  economic 
problem.  He  cannot  afford  to  go  daily  to  the  creamery  or  the 
cream-buying  station,  and  the  result  is  that  he  holds  the  cream 
until  he  has  about  a  can  of  it,  or  enough  to  warrant  him  in 
making  the  trip  to  town.  Cream  of  this  character  is  usually 
more  or  less  sour  when  it  reaches  the  creamery  where  it  is  to  be 
manufactured  into  butter.  Some  of  it  is  too  sour  for  pasteur- 
ization and  the  acidity  must  be  reduced. 

Various  investigations  have  shown  that  butter  churned  from 
high-acid  cream  has  a  tendency  to  become  fishy  when  placed  in 
storage.     The  use  of  bad  starters  has  an  injurious  effect  also. 

One  of  the  leading  butter  houses  in  New  York  has  instructed 
the  creameries  sending  it  butter  not  to  use  starters  during  the 
storage  season.  Investigations  have  demonstrated  that  for 
storage  purposes  low-acid  and  light  salt  give  the  best  results 
under  present  conditions. 


BUTTER  FOR  STORAGE  359 

U.  S.  Bulletin  84,  gotten  out  in  1906,  by  Gray  and  McKay, 
gives  the  results  of  investigations  of  the  manufacture  of  butter 
under  different  conditions,  and  the  keeping  qualities  of  butter 
made  under  these  varying  conditions  and  stored  at  different 
temperatures.  C.  E.  Gray,  dairy  expert  for  the  Dairy  Division 
at  that  time,  had  charge  of  the  manufacturing  of  the  butter, 
which  was  scored  and  criticized  by  McKay  and  Keiffer.  Some  of 
the  butter  for  this  experiment  was  made  at  Topeka,  Kansas, 
from  sour  cream,  and  some  at  Monticello,  Iowa,  from  sweet 
cream.  The  butter  made  from  different  lots  of  cream  was  divided 
and  salted  so  that  it  contained  from  1  to  as  high  as  3  J  per  cent 
salt.  It  was  kept  in  storage  at  —  io°,  io°  and  320  F.,  and 
placed  in  the  vestibule  before  being  scored,  the  temperature  of 
the  vestibule  at  the  time  of  scoring  being  500  to  55  °  F.  After 
the  butter  had  been  in  the  Booth  cold  storage  for  eight  months, 
it  was  removed  to  the  Iowa  Experiment  Station  in  a  refrigerator 
car.  It  was  found  that  on  coming  out  of  storage  the  butter 
made  from  sour  cream  in  nearly  every  case  had  a  pronounced 
fishy  flavor,  and  that  butter  made  from  sweet  cream  containing 
light  salt  kept  much  better  in  storage  than  the  butter  made 
from  the  cream  having  a  high  per  cent  of  acid.  The  two  factors 
that  gave  the  best  results  in  this  butter  were  low  acidity  in  the 
cream  and  low  per  cent  of  salt  in  the  butter. 

It  must  not  be  understood  from  the  above  that  it  is  absolutely 
necessary  to  have  sweet  cream  to  make  butter  that  will  possess 
a  good  keeping  quality.  Where  cream  is  high  in  acid  and  is  free 
from  any  objectionable  flavors,  its  acidity  can  be  reduced  by 
limewater  or  milk  of  lime. 

Some  of  the  highest-selling  butter  found  in  our  leading 
markets  is  made  from  cream  that  was  originally  high  in  acid, 
the  acidity  having  been  reduced  and  the  cream  re-ripened  with  a 
starter.  Very  poor  cream  is  frequently  found  to  be  fairly  low  in 
acidity.  This  is  due  to  inoculation  with  undesirable  organisms, 
through  neglect  of  proper  care  and  cleansing  of  dairy  utensils. 
If  cream  is  high  in  acidity  but  possesses  a  clean  acid  flavor  and 
the  acidity  is  reduced,  the  quality  of  the  butter  will  be  good,  and 
it  has  been  demonstrated  that  butter  made  from  such  cream 


360        COLD  STORAGE  AND  BUTTER  EOR  STORAGE  PURPOSES 

will  come  out  of  storage  in  good  condition.  In  fact,  some  of  the 
leading  butter  dealers  are  now  giving  a  preference,  for  storage 
purposes,  to  butter  made  in  the  large  creameries  where  the 
acidity  of  the  cream  is  reduced  and  the  butter  is  manufac- 
tured under  conditions  that  impart  to  it  a  good  body  and 
texture.  The  statement  made  elsewhere,  that  one  of  the  large 
creameries  made  25  million  pounds  of  butter  last  year  that  graded 
Extras  or  Specials,  demonstrates  what  can  be  and  is  being  done. 
However,  not  all  the  butter  made  in  large  creameries  is  of  this 
quality,  owing  to  lack  of  care  and  skill  in  the  manufacturing. 
Improper  neutralizing,  neglect  to  churn  at  a  sufficiently  low 
temperature  and  improper  working  are  some  of  the  causes  of  the 
production  of  butter  of  low  quality  or  an  inferior  grade.  * 

Working  and  Packing  Butter  for  Storage  Purposes. — Cream 
should  be  cooled  until  the  fat  is  chilled  to  such  a  point  that  the 
granules  of  butter  when  they  gather  will  be  in  sufficiently  firm 
condition.  The  butter  can  then  be  sufficiently  worked  to  thor- 
oughly incorporate  the  salt,  so  that  the  finished  product  will  not 
contain  loose  moisture  and  show  up  leaky  when  packed.  (See 
chapters  on  Churning  and  Working  Butter.) 

Butter  should  be  packed  very  closely  in  the  packages,  whether 
box  or  tub,  to  avoid  air  pockets.  The  tubs  or  boxes  should  be 
thoroughly  steamed  before  paraffining,  and  care  should  be 
exercised  to  make  sure  that  all  parts  of  the  wood  are  coated  with 
hot  paraffin.  Care  should  also  be  taken  to  keep  tubs  and  liners 
in  a  dry  place. 

For  preparing  tubs,  boxes  and  liners  for  packing  butter,  see 
Chapter  XIX. 

Some  butter  is  held  in  storage  for  more  than  a  year,  but  it  is 
very  seldom  that  very  much  butter  is  held  over  nine  months. 

The  Navy  butter  is  put  up  under  government  instruction  and 
is  made  from  sweet  cream,  or  cream  containing  not  more  than 
.25  of  one  per  cent  of  acid,  and  pasteurized  without  the  use  of  a 
starter. 

The  first  to  recommend  churning  the  cream  sweet  was  Mr. 
J.  D.  Leclair  of  St.  Hyacinth  Dairy  School,  Quebec,  Canada. 
His  method  is  outlined  in  a  bulletin  issued  in  1904.     The  cream 


BUTTER  FOR  STORAGE  361 

used  was  from  milk  separated  at  the  creamery  and  contained 
nearly  40  per  cent  fat.  After  being  pasteurized  and  cooled  to 
churning  temperature  it  was  held  for  about  three  hours.  After 
the  cream  was  put  into  the  churn  a  large  per  cent  (25  to  30  per 
cent)  of  starter  was  added  and  churning  followed  immediately. 
Butter  made  in  this  way  secured  first  place  at  the  leading  Cana- 
dian Exhibitions  in  1903.  The  beneficial  effects  of  the  use  of 
good  raw  material  and  a  good  starter  should  again  be  noted. 
Leclair  maintains  that  by  adding  a  starter  to  sweet  cream  and 
churning  immediately  the  flavor-producing  substance  can  be 
developed  in  the  butter  after  it  is  churned.  He  says  that  if 
sweet  cream  is  churned  with  a  portion  of  sour  milk  or  starter 
the  butter  will  have  about  the  same  flavor  after  standing  as  it 
would  have  if  the  cream  were  ripened.  Some  have  tried  to 
improve  the  flavor  of  butter  by  adding  a  starter  directly  to  the 
butter  and  working  it  in  with  the  salt.  According  to  the  Internal 
Revenue  regulations,  butter  of  this  kind  would  be  deemed 
adulterated  and  be  subject  to  a  tax  of  10  cents  a  pound. 


CHAPTER  XXIV 
COOLING  FACILITIES  FOR  CREAMERIES 

One  of  the  most  important  points  in  connection  with  the 
successful  operation  of  a  creamery  is  the  control  of  temperature. 
This  control  is  important  in  the  separation,  pasteurization,  ripen- 
ing and  churning  processes,  and  in  the  use  and  preparation  of 
starters.  Conditions  are  frequently  such  that  the  raw  as  well  as 
finished  dairy  products  need  to  be  stored.  If  temperature  or 
cold  storage  conditions  are  not  under  control,  dairy  products 
will  suffer  in  quality.  Raw  as  well  as  finished  products  are  very 
perishable  and  are  best  when  fresh.  Strictly  and  generally 
speaking,  dairy  products  deteriorate  with  age,  the  nearer  the 
producers  of  the  raw  material,  manufacturers,  and  consumers  of 
the  finished  products  can  be  brought  together,  the  better  it  is. 
Conditions  of  commerce  and  trade  are  such  that  butter  needs  to 
be  preserved  for  some  time  before  it  reaches  the  consumer. 

The  preservation  of  butter  depends  on  the  checking  of  fer- 
mentations affecting  the  flavor  of  this  product,  and  can  best  be 
accomplished  by  the  use  of  a  low  temperature.  There  are  various 
ways  by  which  low  temperature  may  be  obtained  in  creameries. 
The  system  of  refrigeration  to  be  employed  in  a  given  creamery 
should  be  determined  by  local  conditions. 

Cooling  Systems: 

i.  By  the  use  of  natural  ice. 

2.  By  the  use  of  mechanical  refrigeration. 

3.  By  the  use  of  cold  water  alone. 

1.  Most  local  creameries,  within  the  ice-freezing  belt,  make 
use  of  natural  ice.  It  is  by  far  the  most  common  method  of 
refrigeration  employed  in  creameries,  and  undoubtedly  under 
average  local  conditions,  represents  the  most  economic  method 
of  obtaining  low  temperature.     As  a  rule  patrons  have  little 

362 


COOLING  SYSTEMS  363 

work  to  do  during  the  winter  and  are  willing  to  supply  teams 
and  help  for  a  few  days  while  the  ice  is  being  put  up.  The  use  of 
natural  ice  gives  good  satisfaction,  especially  when  good,  pure 
ice  can  be  had  within  a  reasonable  distance  from  the  creamery, 
and  a  proper  and  convenient  place  is  provided  in  which  to  store 
the  ice. 

2.  Mechanical  refrigeration  is  undoubtedly  gaining  favor 
with  creamery-men,  as  is  evidenced  by  the  increased  number 
of  mechanical  refrigera ting-plants  installed  in  various  creameries. 
The  reasons  for  this  increase  are  due,  first,  to  centralization  of 
creameries,  second,  to  mild  winters  in  certain  sections  and  a  con- 
sequent lack  of  natural  ice,  and  third,  to  the  greater  convenience 
of  mechanical  refrigeration  if  properly  operated. 

Centralized  creameries  have  so  much  more  cooling  to  do 
than  a  local  creamery,  that  a  mechanical  refrigerating-plant 
best  serves  their  needs.  Often  centralized  plants  are  located  in 
large  cities  where  an  ice-manufacturing  plant  and  cold  storage 
plant  may  be  run  successfully  in  connection  with  the  creamery. 
Prof.  Erf  1  has  conducted  some  experiments  relative  to  the  com- 
parative cost  of  the  two  systems  for  creamery  use.  The  fol- 
lowing table  shows  the  results,  and  indicates  the  comparative 
cost  of  cooling  ioo  pounds  of  butter  to  300  F.,  including  the 
cost  of  cooling  the  cream  during  manufacturing  processes. 
These  figures  are  also  based  upon  a  run  of  10,000  pounds  of  milk 
per  day. 

1234 
Cents  Cents  Cents        Cents 

Natural-ice  system 20.1         18.2         17.5        17. 1 

Mechanical  refrigeration 17.8         17. 1         16.9         16.8 

The  different  columns  (1,  2,  3,  4)  indicate  different  insulating 
material  used,  which  cannot  here  be  elaborated  upon,  except 
to  say  that  it  pays  to  insulate  thoroughly. 

The  above  results  indicate  that  mechanical  refrigeration  is  a 
little  the  cheaper.  Its  cost  is  quite  constant  under  different 
conditions,  while  the  cost  connected  with  storing  and  using  nat- 
ural ice  will  vary  greatly  according  to  different  localities. 

1  Creamery  Journal. 


364  COOLING  FACILITIES  FOR  CREAMERIES 

3.  Under  certain  conditions,  intentional  or  unintentional,  a 
creamery  must  be  run  without  the  use  of  ice,  and  without 
mechanical  refrigeration.  In  such  a  case  cold  water  is  a  necessity. 
One  of  the  authors  successfully  operated  a  creamery  for  one 
season  without  any  other  cooling  agent  than  water.  The  winter 
season  had  been  warm  and  no  ice  was  obtained  nor  was  it  obtain- 
able at  a  reasonable  cost.  There  was  no  room  in  the  creamery 
for  a  mechanical  refrigera ting-plant,  and  even  if  there  had  been, 
no  money  was  available  with  which  to  purchase  such  cooling 
facilities.  The  only  thing  to  do  was  to  close  the  creamery  or  cool 
with  water. 

The  latter  method  was  resorted  to.  The  creamery  was 
fortunate  in  having  an  unlimited  supply  of  pure  cold  water 
coming  from  a  mountain  stream. 

This  water  was  made  effective  for  cooling  purposes  by 
directing  a  constant  flow  through  a  galvanized  iron  tank  in  the 
refrigerator.  The  ice-box  on  the  inside  of  the  refrigerator  was 
removed,  and  a  closed  galvanized  iron  tank  put  in  its  place. 
This  tank  was  connected  with  an  inflow  and  overflow  at  the  top. 
A  faucet  for  draining  the  tank  was  provided  at  the  bottom  in  one 
corner.  The  tank  was  made  straight  on  the  side  next  to  the  wall, 
but  sloping  towards  the  wall  on  the  side  facing  the  refrigerator 
room.  This  was  done  so  as  to  allow  the  dampness  or  sweat  col- 
lecting on  the  outside  to  run  down  the  sides  and  be  collected  in  a 
trough,  which  conveyed  it  to  the  outside.  A  trap  was  connected 
with  this  outlet  so  as  not  to  let  in  warm  air.  Such  an  arrange- 
ment gave  very  good  satisfaction,  though  not  so  effective  in 
cooling  as  ice. 

The  cream  was  cooled  and  kept  cold  by  circulating  a  constant 
stream  of  water  through  the  vat-jackets.  The  temperature  of 
the  water  was  never  above  50 °  F. 

The  butter  was  disposed  of  locally  while  fresh.  In  cream- 
eries where  it  is  necessary  to  hold  butter  any  length  of  time,  this 
system  is  undoubtedly  less  satisfactory,  but  under  the  above- 
mentioned  conditions  it  gave  good  satisfaction. 

The  water- tank  should  never  be  made  from  wood,  as  wood 
is  a  very  poor  conductor  of  heat.     Heavy  galvanized  iron  is  best. 


NATURAL  ICE  SYSTEM  365 


NATURAL  ICE  SYSTEM 


Kind  of  Ice-house. — When  natural  ice  is  stored,  the  first  con- 
sideration is  a  good  ice-house  conveniently  located  to  the  cream- 
ery and  refrigerator.  When  the  creamery  is  first  planned  and 
built  the  ice-house  should  at  the  same  time  be  provided  for. 
It  should  preferably  be  adjacent  to  the  refrigerator,  so  that  the 
ice  can  be  transferred  directly  from  the  house  into  the  cooler, 
thus  obviating  much  loss  of  ice  and  decreasing  labor. 

The  various  parts  of  the  building,  embracing  the  many 
details,  will  not  here  be  enlarged  upon,  inasmuch  as  they  can 
be  more  advantageously  shown  in  plans.  Students  are  referred 
to  the  different  views  shown  in  this  chapter. 

As  will  be  seen,  the  construction  of  the  ice-house  depends 
to  some  extent  upon  the  location  and  kind  of  refrigerator  to  be 
used.  There  are  at  least  two  different  ways  of  locating  the 
refrigerator  in  relation  to  ice-house:  (i)  Where  the  refrigerator  is 
entirely  separate  from  the  ice-house,  the  ice  to  be  transferred 
and  placed  either  overhead  or  on  one  side  of  the  refrigerator. 
(2)  Where  the  refrigerator  is  combined  with  the  ice-house  and  the 
ice  is  not  moved  for  cooling  purposes.  This  in  turn  may  be 
arranged  so  as  to  have  the  ice  storage  overhead  or  on  one  side  of 
the  refrigerator.  The  ice-house  needed  in  connection  with  this 
second  method  differs  chiefly  from  that  of  the  first  in  that  better 
insulation  is  necessary  and  no  ice-packing  material  is  used,  except 
on  top.  This  latter  type  of  creamery  refrigerator,  even  though 
more  expensive,  is  to  be  highly  recommended,  chiefly  because 
labor  is  decreased,  and  the  low  temperature  is  uniformly  main- 
tained. 

Reasonably  high  ground  affords  a  good  location  for  an  ice- 
house. It  is  of  importance  that  the  ground  should  be  thoroughly 
drained  before  the  ice-house  is  built.  If  the  ground  is  high,  dry, 
and  gravelly,  no  drainage  may  be  needed,  but  under  most  con- 
ditions a  drain  should  be  run  through  the  bottom.  This  drain 
should  not  be  very  deep.  If  the  area  to  be  drained  is  so  large 
that  one  drain  will  not  carry  off  the  water,  it  is  better  to  use  two 
drains  rather  than  to  have  one  deep  one. 


366 


COOLING  FACILITIES  FOR  CREAMERIES 


1 


>>s////////w//;^^^^ 


■■= 


D 


3Spaoe  b^wean  Btud^filled  with}fehaTlngs   | 


Drain  -*• 


Cooling  Room 


PLAN 


Second  or  Attic  Floor 


Space  between  Joists  filled  with  Shavings 


SECTION 
Fig.  129.— Refrigerator  with  ice  overhead. 


NATURAL  ICE  SYSTEM 


367 


368 


COOLING  FACILITIES   FOR   CREAMERIES 


Size  and  Shape  of  Ice-house. — The  plan  of  the  ice-house 
should  be  as  nearly  square  as  consistent  with  available  space.     A 


%"*  6"d.  &  M.  Fencing. 
«-  Waterproof  Paper. 
%  Surfaced  Boards. 


%  Surfaced  Boards. 

Waterproof  Paper. 
jfa  6D.  &  M.  Fencing. 


%  x  6  D.  & 
Fencing 
Waterproof 

Paper. 
ll'x  8  drop 

siding 
Doors  lapped 
as  shown 


^ Space  filled  with  shavings 

through  small  outside  door  at  top. 


2x6  Surf.  Plank  2  apart 

V//////A  mm&  vw///a 


2x8  Joists-24  Cen.filled  with  planer  shavings 
Joists  to  slant  towards  center  of  house 


TV/.fi '-'<*. 


Gravel  under  joists  well 
tamped 


131. — Construction  detail  of  ice-house. 

square  building,  having  a  certain  length  of  wall  around  it,  will 
hold  more  ice  than  an  oblong  building  having  an  equal  number  of 


NATURAL   ICE   SYSTEM  369 

feet  of  outside  walls.  The  building  should  also  be  high  in  pro- 
portion to  width  and  length.  This  will  tend  to  preserve  the  ice, 
as  proportionately  less  top  surface  is  exposed  to  the  air. 

The  size  of  the  building  will  vary  according  to  (i)  amount 
of  milk  handled  at  the  creamery,  (2)  whether  ice  is  sold  from 
creamery,  and  (3)  whether  ice  is  used  for  any  other  purposes, 
such  as  ice-cream  freezing,  cream  shipping,  etc.  For  creamery 
uses,  the  only  basis  on  which  to  estimate  is  the  amount  of  milk 
received. 

For  example,  suppose  a  creamery  is  receiving  12,000  pounds 
of  milk  daily.  This  milk  will  produce  about  2000  pounds  of 
cream  and  about  600  pounds  of  butter.  Suppose  that  the 
cream  needs  to  be  cooled  from  900  F.  down  to  400  F.  or  a  range 
of  500  F.  One  pound  of  ice  will  cool  about  142  pounds  of  water 
i°  F.  Calculations  are  made  with  water  as  basis.  The  results 
will  thus  be  a  little  too  high,  but  subsequent  corrections  will  be 
made.  If  1  pound  of  ice  will  cool  142  pounds  of  cream  i°F., 
it  will  require  50  pounds  of  ice  to  cool  that  amount  of  cream  500  F. 
By  calculation  from  these  figures  we  find  that  about  0.35  of  a 
pound  of  ice  is  required  to  cool  each  pound  of  cream  50 °  F.  and 
for  cooling  2000  pounds  of  cream  it  will  require  700  pounds.  If  it 
takes  700  pounds  of  ice  daily  for  cooling  the  cream  for  eight 
months  of  the  year,  which  is  about  the  time  the  cream  would  have 
to  be  cooled  by  artificial  means,  it  would  take  168,000  pounds  of 
ice  per  year.  As  the  specific  heat  of  cream  is  only  about  0.7, 
the  final  amount  needed  for  cooling  the  cream  would  be  only 
117,600  pounds,  or  about  59  tons. 

The  next  consideration  is  the  ice  needed  for  cooling  the  butter. 
Roughly  speaking,  there  will  be  about  6co  pounds  of  butter. 
Suppose  the  butter  needs  to  be  cooled  30 °  F.  Granting  that  the 
specific  heat  of  butter  is  the  same  as  that  of  water,  it  would 
require  30  pounds  of  ice  to  cool  142  pounds  of  butter  300  F. 
There  will  therefore  be  needed  daily  1 26  pounds  of  ice  for  cooling 
the  butter.  As  the  specific  heat  of  butter  is  only  about  0.4, 
51  pounds  of  ice  are  necessary  daily.  For  eight  months  12,240 
pounds  will  be  needed.  The  amount  of  ice  needed  in  a  refrigerator 
above  that  needed  for  cooling  the  butter  cannot  be  calculated. 


370 


COOLING  FACILITIES   FOR   CREAMERIES 


We  may  count  on  25  per  cent  radiation  and  25  per  cent  as  an 
allowance  for  cooling  tubs  and  packages.     The  total  ice  needed 


p  s 

3  § 


M 


si 


3i 


II 


«                                             1 

III 

1 

I 

1 

9                     1 

' 

IP1' 

op  Sidi 

1 

1 

ft       ■ 

:j 

2 

«tH 

III 

X 

1 

1 

a-aa — 

i 

This  top  door  12'high 
for  the  purpose  of  filling 
space  with  shavings  after 
ice  is  in 

1 

l1 

I      UJ 


I    LU 

I  «> 


for  cooling  the  butter  will  then  be  24,480  pounds,  or  about  12 \ 
tons. 


NATURAL  ICE  SYSTEM 


371 


Counting  on  20  per  cent  loss  incidental  to  transportation 
and  melting  in  the  ice-house,  89  tons  of  ice  are  needed  for  cooling 
the  cream  and  butter  the  number  of  degrees  mentioned  arJove. 


One  cubic  foot  of  ice  at  320  F.  weighs  57.5  pounds.  If  1 
cubic  foot  of  ice  weighs  57.5  pounds,  89  tons  would  occupy  a 
space  equal  to  3093  cubic  feet,  and  would  require  an  ice-house  of 
dimensions  approximately  as  follows:   16  feet  high,  14  feet  wide, 


372  COOLING   FACILITIES   FOR   CREAMERIES 

and  14  feet  long.  These  dimensions  are  given  only  as  examples. 
The  height,  width,  and  length  may  need  to  be  changed  to  con- 
form with  local  conditions.  One  thing  should  be  kept  in  mind — 
it  is  always  better  to  have  an  ice-house  a  little  too  large  rather 
than  too  small. 

Filling  the  Ice-house. — The  chief  objects  to  be  sought  in 
packing  ice  into  an  ice-house  already  properly  constructed, 
are:  first,  to  exclude  circulation  of  air  through  the  mass  of  ice 
and  thus  prevent  melting;  second,  to  pack  it  in  such  a  manner 
that  it  can  easily  be  removed  in  whole  blocks;  third,  to  pack 
it  with  material  that  will  leave  the  ice  as  clean  as  is  consistent 
with  other  important  objects  sought. 

The  packing  material  which  is  most  commonly  usdd  in  the 
central  western  states  is  sawdust.  This  is  very  efficient  in 
excluding  air,  lasting,  and  usually  cheap,  but  soils  the  ice 
so  that  considerable  water  needs  to  be  used  to  rinse  it,  and  as  a 
consequence,  considerable  ice  is  wasted.  Straw  is  used  success- 
fully. It  leaves  the  ice  much  cleaner,  but  is  not  so  effective  in 
preserving  the  ice.  Shavings  are  good,  but  as  a  rule  are  too 
expensive  and  not  available.  Some  use  no  packing  material 
other  than  ice  and  snow.  When  the  blocks  of  ice  are  put  into 
the  ice-house,  they  are  packed  closely  together.  A  man  with  a 
hatchet  chips  the  blocks  of  ice  in  such  a  way  as  to  fit  them 
snugly  together,  and  the  small  cracks  are  filled  with  fine  ice  and 
snow.  The  experience  of  the  authors  is  that,  by  this  method, 
the  blocks  of  ice  are  likely  to  freeze  solidly  together,  so  that  the 
ice  cannot  be  removed  without  breaking  it  up  into  irregular 
pieces.     This  is  hard  work,  and  considerable  ice  is  wasted. 

Another  method  of  filling  ice-houses  in  successful  use  is  that 
of  running  a  shallow  layer  of  water  into  the  building  and  allowing 
it  to  freeze.  The  doors  in  the  ice-house  are  opened  during  a 
protracted  period  of  cold  weather.  The  bottom  of  the  ice- 
house is  covered  with  building-paper.  Water  is  run  on  top  of 
this  and  allowed  to  freeze  until  a  layer  of  ice  about  a  foot  in 
thickness  has  been  obtained.  Then  another  layer  of  paper  is 
made  to  cover  the  ice  and  more  water  flooded  on  and  frozen. 
This  process  is  continued  until  the  ice-house  is  filled.     The  papei 


NATURAL  ICE  SYSTEM  373 

between  the  layers  prevents  the  ice  from  freezing  into  one  solid 
mass,  and  facilitates  its  removal. 

When  the  ice  is  stored  in  an  insulated  house,  combined  with 
the  refrigerator,  no  packing  material  is  used  except  on  the  top  of 
the  ice.  Shavings  are  good  to  pile  on  the  top  of  ice  when  the 
ice-house  has  been  filled.  They  are  clean  and  effective  in  pre- 
serving the  ice. 

The  cost  of  filling  an  ice-house  with  natural  ice,  obtainable 
within  a  distance  of  about  8  miles,  will  vary  in  different  localities, 
but  may  be  said  to  range  between  $0.60  and  $1.25  per  ton.  The 
creamery  furnishes  a  man  to  pack  it  into  the  ice-house. 

Source  of  Ice. — The  ice  for  creamery  use  should  be  obtained 
from  as  pure  water  as  possible.  A  large  running  stream  is  always 
better  than  a  small  polluted  stream.  Usually  the  creamery  can 
co-operate  with  butchers,  restaurants,  hotel-men,  and  other 
local  ice-users  in  building  a  dam  in  a  suitable  stream.  The  ice 
can  also  as  a  rule  be  harvested  cheaper  by  co-operation. 

Some  creameries  have  constructed  ice-ponds  near  the  ice- 
house. If  there  is  a  clay  or  impervious  bottom,  this  works  suc- 
cessfully and  economically.  The  pond  is  filled  and  kept  filled 
from  the  creamery  water-supply  or  from  a  tile  drain  inlet. 
Care  should  be  taken  not  to  use  stagnant  water  or  water  in  which 
weeds  and  other  rubbish  have  been  allowed  to  accumulate. 
The  pond  should  be  deep  enough  so  that  the  water  will  not  freeze 
to  the  bottom  and  produce  dirty  ice.  The  pond  should  also  be 
filled  with  water  to  overflowing  when  freezing  is  begun;  other- 
wise slush  and  snow  are  likely  to  accumulate  together  with  dust 
from  the  fields  and  roads,  producing  impure  ice. 

The  ice  is  best  when  frozen  from  the  top  down.  A  hole  is 
bored  in  the  ice  and  kept  open  during  the  freezing  process. 
Through  this  opening  the  pond  is  supplied  with  water  as  rapidly 
as  it  subsides.  When  the  water  is  solidly  up  against  the  bottom 
of  the  ice  it  will  show  in  the  opening  or  hole  in  the  ice. 

To  construct  an  ice-pond  on  gravelly  soil  is  useless,  and  to 
pack  such  a  pond  with  a  sufficiently  thick  layer  of  clay  to 
prevent  leakage  of  water  is,  under  most  conditions,  imprac- 
ticable. 


374  COOLING   FACILITIES   FOR   CREAMERIES 


USE   OF   ICE   IN   COOLING   CREAM 

i.  Directly. 

2.  Indirectly. 

i.  The  cooling  of  cream  in  creameries  by  putting  ice  directly 
into  the  cream  has  been  much  practiced  in  the  past.  The 
method  is  yet  used  considerably,  especially  where  the  old  open 
vats  are  still  in  use.  Some  of  these  open  vats  are  jacketed 
and  some  are  not.  Cream  in  unjacketed  vats  could  not  well 
be  cooled  in  any  other  way  than  by  using  ice  directly  in  the 
cream  and  stirring  until  cold.  To  keep  cold  any  length  of  time, 
considerable  excess  of  ice  needs  to  be  used. 

Such  a  method  of  cooling  cream  has  its  advantages  as  well  as 
disadvantages.     The  latter,  however,  clearly  outweigh  the  former. 

The  advantages  are  that  the  cream  can  be  cooled  in  a  very 
short  time,  and  it  does  not  require  any  special  investment 
for  up-to-date  ripening-vats,  nor  special  machinery  for  the  pur- 
pose of  pumping  the  cooling  medium. 

The  chief  disadvantages  are :  first,  impurities  and  undesirable 
germs  are  liable  to  be  introduced,  which  injure  the  quality  of 
the  cream  and  otherwise  work  harm  to  the  quality  and  keeping 
property  of  the  butter;  second,  the  melting  of  the  ice  would  dilute 
the  cream.  This  would  render  the  cream  less  sour,  impart  a 
marked  flat,  insipid  taste  to  the  cream  and  butter,  and  produce 
more  buttermilk  which,  if  it  contained  a  certain  per  cent  fat, 
would  mean  a  greater  loss  of  fat  during  the  churning  process. 

The  use  of  ice  directly  in  the  cream  for  cooling  purposes 
should  not  be  resorted  to  unless  it  is  necessary.  With  the 
best  quality  of  cream  this  method  is  still  more  unsatisfactory, 
as  it  greatly  lowers  the  quality  of  the  butter.  With  cream  in 
very  poor  condition  previous  to  ripening,  the  chances  for  lowering 
the  quality  of  butter  are  not  so  great. 

2.  The  indirect  cooling  of  cream  with  ice  is  by  far  the  better 
method.  With  the  use  of  our  up-to-date  ripening-vats,  the 
cooling  of  cream  is  an  easy  matter;  but  where  the  creamery  is 
already  in  possession  of  a  good  open  vat  and  the  management  not 
disposed  to  discard  it  to  install  a  new  one,  the  question  is  different. 


MECHANICAL   REFRIGERATION  375 

Some  open  vats  have  a  jacket  and  special  open  space  at  one 
end  for  holding  crushed  ice.  These  vats  will  control  and  hold 
temperature  better  than  those  that  simply  have  a  jacket  around 
them.  The  cooling  of  cream  on  a  large  scale  by  circulating  ice- 
water  through  the  jacket  is,  at  best,  a  slow  process,  usually  too 
slow  to  be  effective  and  practical. 

This  cooling  process  is  carried  out  by  mixing  the  ice  and 
water  together  in  a  separate  vat  to  which  a  rotary  pump  is 
attached,  forcing  the  water  through  the  jacket  and  again  return- 
ing it  to  the  ice  and  water- tank  to  be  cooled.  The  slowness  of 
this  cooling  process  can  in  a  measure  be  overcome  by  mixing  salt 
with  the  ice  and  water.  This  will  cause  the  ice  to  melt  faster, 
and  consequently  cool  the  brine  to  a  lower  degree  of  temperature 
than  it  is  possible  to  obtain  with  water  and  ice. 

In  case  it  is  desirable,  a  set  of  coils  can  be  made  which  will 
fit  into  the  open  vat.  The  inlet  and  outlet  of  these  coils  can  be 
connected  by  means  of  rubber  hose  with  the  pipes  conveying  the 
brine  to  and  from  the  ripener.  The  coils  can  be  made  to  move 
up  and  down,  by  means  of  a  rope  attached  to  and  leading  from 
the  coils  through  a  pulley  near  the  loft  and  fastened  to  a  small 
crank  at  the  end  of  a  shaft.  When  the  shaft  turns  the  crank 
will  also  turn  and  cause  the  coils  in  the  vat  to  move  up  and  down. 
In  the  absence  of  a  special  up-to-date  ripener,  this  manner  of 
cooling  works  very  satisfactorily. 

A  butter  refrigerator  containing  a  tank,  as  already  described, 
could  be  cooled  by  pumping  brine  through  it  in  a  similar 
manner,  as  described  for  cream  cooling,  except  that  no  coils  are 
needed. 

MECHANICAL  REFRIGERATION 

Application  in  Creameries. — Mechanical  refrigeration  on  a 
small  scale  has  been  considered  expensive  and  impracticable 
until  within  recent  years.  The  science  of  producing  cold  arti- 
ficially has  been  simplified  and  reduced  to  such  a  practical 
basis  that  it  is  now  used  in  many  large  plants  as  well  as  in  smaller 
plants  where  formerly  natural  ice  was  used  altogether.  Where 
at  least  10,000  pounds   of    milk,  or  its    equivalent  in  cream, 


376  COOLING  FACILITIES  FOR  CREAMERIES 

are  received  daily  during  the  summer  months,  mechanical 
refrigeration  is  considered  practicable. 

On  another  page  a  table  of  comparative  costs  of  natural  ice 
and  mechanical  refrigeration  is  given.  It  was  also  stated  in 
that  connection  that  the  cost  of  mechanical  refrigeration  would 
vary  under  different  conditions.  The  chief  factors  affecting  the 
cost  of  mechanical  refrigeration  may  be  said  to  be  similar  to  those 
affecting  the  economic  running  of  the  remaining  machinery,  such 
as  kind  of  fuel  used,  skill  of  firemen,  style  and  condition  of  boiler, 
proportion  of  boiler  power  to  work  done,  the  correlative  size  of  all 
machinery,  kind  of  insulation  and  care  of  cooling-rooms,  and 
efficiency  of  compressor  and  whole  refrigerating  system. 

Chemicals  Used  for  Mechanical  Refrigeration. — The  most 
common  substances  used  in  mechanical  refrigeration  are  ammo- 
nia and  carbonic  acid.  A  number  of  others  are  in  use,  but 
from  a  creamery  standpoint,  these  only  are  of  importance. 
Ammonia  is  the  most  used.  It  is  efficient,  cheap,  and  not  so 
dangerous  to  life  and  property  as  are  some  of  the  others.  Anhy- 
drous ammonia  has  a  boiling-point  of  27 °  below  zero  at  atmos- 
pheric pressure.  The  latent  heat  of  ammonia  is  also  great. 
Ammonia  has  great  chemical  stability,  and  is  not  explosive  in 
nature;  it  attacks  copper  and  brass,  but  has  no  effect  upon  iron 
and  steel  pipes.  If  ammonia  should  escape  through  a  leak  into  a 
room,  the  operator  can  protect  himself  from  the  effects  of  the  gas 
by  breathing  through  a  wet  sponge  held  in  the  mouth.  Ammonia 
leaks  may  be  detected  by  holding  a  glass  rod  dipped  in  hydro- 
chloric acid  to  the  place  where  the  leak  may  be.  When  ammonia 
comes  in  contact  with  hydrochloric  acid,  white  fumes  are 
formed. 

Carbonic  acid  is  used  considerably  in  Europe,  and  is  chiefly 
favored  because  the  gas  is  not  highly  poisonous;  in  case  of 
leak  it  does  not  soil  contents  of  refrigerator,  and  it  liquefies 
at  a  high  temperature  (900  to  ioo°  F.),  and  is  therefore  favored 
in  tropical  climates. 

Principles  of  Producing  Cold  Artificially. — The  chief  principle 
involved  in  producing  artificial  cold  is  that  when  a  substance 
passes  from  a  liquid  into  a  gaseous  state,  a  definite  amount  of 


MECHANICAL  REFRIGERATION  377 

latent  heat  is  absorbed.  When  water  in  a  kettle  on  the  stove 
begins  to  boil  and  passes  off  into  steam,  no  higher  temperature 
can  be  reached.  No  matter  how  much  heat  is  applied  under 
those  same  conditions,  the  temperature  remains  the  same.  This 
extra  heat  is  used  in  transforming  the  water  into  steam.  If  this 
steam  were  confined,  and  that  heat  removed,  by  cooling,  the 
steam  would  again  pass  into  a  liquid  state.  We  are  familiar 
with  the  coolness  produced  by  rapid  evaporation  of  perspiration 
from  the  body.  Mechanical  refrigeration  is  virtually  a  process 
of  evaporation  of  the  cooling  media,  during  which  heat  is  absorbed, 
and  liquefaction  of  the  cooling  medium  by  compression  and  cool- 
ing to  remove  that  absorbed  heat.  To  increase  the  ability  of  the 
cooling  medium  to  absorb  heat  it  is  compressed  and  liquefied. 
So  it  may  be  said  that  in  any  compression  refrigerating  system 
three  separate  operations  are  necessary  to  form  the  complete 
cycle  of  mechanical  refrigeration,  viz. : 
i.  Compression  of  the  ammonia  gas. 

2.  Condensation  of  the  ammonia  gas. 

3.  Expansion  of  the  ammonia  gas. 

1 .  The  machine  which  causes  the  compression  of  the  ammonia 
gas  is  called  the  compressor.  In  construction  it  is  much  like  a 
steam-engine.  Small  machines  are  single,  but  large  machines  are 
double  acting.  Gas  is  drawn  in,  on  the  suction  stroke,  com- 
pressed and  discharged  on  the  return  stroke.  The  pressure  gen- 
erated varies  between  120  and  175  pounds  per  square  inch. 
During  the  compression  heat  is  developed  in  proportion  to  pres- 
sure exerted.  The  greater  the  pressure  the  higher  the  tempera- 
ture of  the  gas.  Part  of  the  heat  of  compression  is  carried  off  by 
means  of  a  continuous  stream  of  water  running  through  a  jacket 
around  the  cylinder. 

2.  From  the  compressor  the  gas  is  forced  through  the  pipes 
into  the  condensing  coils,  in  which  the  warm  compressed  gas  is 
cooled  still  more.  When  sufficient  heat  has  been  removed  from 
this  gas,  it  assumes  a  liquid  condition  and  is  ready  to  expand  into 
a  gaseous  form  for  the  purpose  of  absorbing  heat  and  producing 
cold.  During  the  cooling  and  condensing  processes  each  pound 
of  ammonia  parts  with  about  560  units  of  heat,  which  amount 


378  COOLING   FACILITIES   FOR   CREAMERIES 

can  again  be  absorbed  when  it  expands  into  gas  at  the  lower 
pressure. 

3.  This  liquefied  gas,  which  is  still  under  great  pressure,  is 
then  admitted  through  what  is  termed  the  expansion- valve. 
This  valve  is  especially  constructed  for  that  purpose,  and  has 
only  a  very  minute  opening  in  it  for  the  admission  of  the  liquid 
ammonia.  On  the  expansion  side  the  pressure  is  low  (20  to 
30  pounds).  As  the  liquid  ammonia  emerges  from  the  high- 
pressure  side  through  the  expansion-valve  into  the  expansion 
side,  it  forms  a  gas.  This  expanded  gas  may  then  be  circulated 
through  coils  for  cooling  purposes.  From  there  it  passes  back 
into  the  suction  side  of  the  compressor  ready  to  go  through 
another  similar  cycle. 

From  the  above  description  it  will  be  seen  that  there  are  two 
sides  to  the  system,  the  expansion  side  and  the  compression 
side.  The  compression  side  extends  from  the  compressor  to 
the  expansion- valve ;  the  expansion  side  from  the  expansion- 
valve  to  the  suction  side  of  the  compressor,  inclusive. 

Transferring  the  Cold. — The  methods  of  transferring  the  cold 
to  the  different  places  in  the  building  vary.  There  are  two  sys- 
tems, viz.: 

1.  Direct  Expansion. 

2.  Brine  System. 

1.  By  the  direct-expansion  system  the  condensing-pipes  are 
extended  to  the  room  or  place  at  which  the  cooling  is  to  be  done. 
An  extended  set  of  expansion  coils  then  convey  the  gas  which 
absorbs  the  heat.  A  lower  temperature  can  be  produced  by  this 
method  than  with  the  brine  system. 

2.  In  the  brine  system  a  large  brine- tank  is  placed  some- 
where in  the  creamery  at  a  place  most  convenient  with  respect 
to  cooling.  This  tank  contains  a  strong  solution  of  brine.  The 
chief  reason  why  brine  is  used  in  preference  to  water  is  that 
brine  has  a  very  low  freezing-point.  This  will  vary  with  dif- 
ferent degrees  of  saturation. 

Either  one,  sodium  chloride  (common  salt),  or  calcium 
chloride,  may  be  used  for  brine.  The  latter  is  considered  the 
better  chiefly  because  it  is  not  so  hard  on  the  pipes  and  it  keeps 


MECHANICAL  REFRIGERATION 


379 


the  brine  pipes  cleaner  than  does  a  salt  brine.     The  tables  give 
properties  of  brine  made  from  these  two  substances. 


SHOWING  PROPERTIES  OF  SOLUTION  OF  SALT.     (SIEBLY). 
(Chloride  of  Sodium). 


Per  Cent 

of  Salt  by 

Weight 

Pounds 
Salt  per 
Gallon 
of  Solu- 
tion 

Degrees 
on  Sal- 
ometer 

at  60 °  F. 

Weight 
per  Gal. 
at  39°  F. 

Specific 

Gravity 

at  39°  F. 

4°C. 

Specific 
Heat 

Freezing- 
point, 
Fahr. 

Freezing- 
point, 
Celsius 

i 

0.084 

4 

8.40 

1.007 

0.992 

30.5 

-  0.8 

2 

0.169 

8 

8 

46 

1-015 

0.984 

29-3 

—   1 

5 

2-5 

0.  212 

10 

8 

5o 

1. 019 

0.980 

28.6 

—   1 

9 

3 

0.256 

12 

8 

53 

1.023 

0.976 

27.8 

—   2 

3 

3-5 

0.300 

14 

8 

56 

1.026 

0.972 

27.1 

—   2 

7 

4 

o.344 

16 

8 

59 

1.030 

0.968 

26.6 

-  3 

0 

5 

o.433 

20 

8 

65 

1.037 

0.960 

25.2 

-  3 

8 

6 

0.523 

24 

8 

72 

1  045 

0.946 

23-9 

-  4 

5 

7 

0.617 

28 

8 

78 

1  053 

0.932 

22.5 

-  5 

3 

8 

0.708 

32 

8 

85 

1 .061 

0.919 

21.2 

-  6 

0 

9 

0.802 

36 

8 

91 

1.068 

0.005 

19.9 

-  6 

7 

10 

0.897 

40 

8 

97 

1 .076 

0.892 

18.7 

-  7 

4 

12 

1.092 

48 

9 

10 

1. 091 

0.874 

16.0 

-  8 

9 

15 

1.389 

60 

9 

26 

1. us 

0.855 

12.2 

—  11 

0 

20 

1.928 

80 

9 

64 

1155 

0.829 

6.1 

-14 

4 

24 

2.376 

96 

9 

90 

1. 187 

o.795 

1.  2 

-17 

1 

25 

2.488 

100 

9 

97 

1 .  196 

0.783 

0.5 

-17 

8 

26 

2.610 

104 

10 

04 

1 .  204 

0.771 

—  1. 1 

-18 

4 

PROPERTIES  OF  SOLUTION  OF  CHLORIDE  OF  CALCIUM.     (SIEBLY) 


Per  Cent  by 
Weight 

Specific  Heat 

Specific 

Gravity  at  6o° 

Fahr. 

Freezing-point 
in  Degrees  Fahr. 

Freezing-point 
in  Degrees  Cels. 

1 

0.996 

1 .009 

3i 

-  0.5 

5 

0.964 

1  043 

27-5 

-   2.5 

10 

0.896 

1.087 

22 

-  5-6 

15 

0.860 

1   134 

15 

-  96 

20 

0.834 

1. 182 

5 

-14.8 

25 

0.79c 

1-234 

-  8 

—  22. 1 

380  COOLING  FACILITIES  FOR   CREAMERIES 

The  expansion-coils  pass  through  the  brine- tank  and  cool 
the  brine.  Special  pumps  force  the  cold  brine  through  pipes 
to  the  cream  vat,  cooling  coils,  ice-cream  freezer,  etc. 

For  creameries  the  brine  system  is  the  only  practical  system. 
It  is  preferred  because,  first,  cold  can  be  stored  in  an  insulated 
brine-tank  and  used  at  will  without  running  the  compressor. 
(In  case  of  a  prolonged  stoppage  due  to  some  accident  a  brine 
made  by  a  mixture  of  ice-water  and  salt  could  be  temporarily 
substituted);  second,  less  ammonia  is  required  to  charge  the 
system;  third,  fewer  couplings  and  less  ammonia  pipes  are 
necessary.  This  latter  would  decrease  the  danger  of  ammonia 
leakage  and  cost  of  pipes.  » 


CHAPTER  XXV 
ECONOMIC  OPERATION  OF  CREAMERY 

Inasmuch  as  it  is  impossible  within  the  limited  space  of  this 
work  to  enter  upon  a  detailed  discussion  of  the  various  principles 
and  practices  of  operating  boilers,  engines,  mechanical  refrig- 
erators, and  other  creamery  machinery,  only  a  few  of  the  chief 
factors  common  to  creamery  practice  and  affecting  economic 
operation  shall  be  discussed  here.  For  more  complete  informa- 
tion students  are  referred  to  works  treating  specially  of  these 
phases. 

Firing  the  Boiler. — Much  fuel  can  be  wasted  or  saved  accord- 
ing to  the  completeness  with  which  the  combustion  occurs. 
This  again  depends  upon  the  manner  of  firing,  upon  the  regula- 
tion of  the  draught,  and  upon  the  kind  of  boiler.  The  fire 
on  the  grates  should  never  be  too  thick  nor  should  too  much 
coal  be  loaded  on  the  fire  at  any  one  time.  A  thin,  even  fire 
permits  of  a  more  complete  combustion  than  is  possible  when 
clinkers  and  cinders  are  allowed  to  accumulate  on  the  bottom  of 
the  fire  and  a  heap  of  unburned  coal  on  top.  By  this  latter 
method  of  firing,  the  grates  are  likely  to  be  injured. 

To  get  the  most  heat  from  the  coal  the  draught  should  be 
regulated.  The  combustible  part  of  the  coal  is  of  two  kinds: 
first,  the  fixed  carbon,  and  second,  the  volatile  matter.  The 
former  is  the  coke  or  the  part  of  coal  which  is  seen  on  the  grates 
as  a  mass  of  glowing  fire.  The  latter  consists  of  the  gases  which 
pass  off  when  a  certain  temperature  is  reached,  and  which,  when 
mixed  with  a  certain  amount  of  air  at  a  given  temperature,  will 
burn.  The  heavy  black  trail  of  smoke  seen  rising  from  chimneys 
is  partially  wasted  coal.  If  the  grates  are  choked  with  a  thick 
fire,  no  air  can  pass  through,  and  the  volatile  parts  of  coal  pass 
off  without  being  burned. 

381 


382 


ECONOMIC   OPERATION  OF   CREAMERY 


Burning  Wood  or  Coal. — In  some  localities  this  question  is 
of  minor  importance,  as  conditions  may  be  such  that  .coal  only- 
can  be  used.  In  other  sections,  where  both  are  obtainable,  it 
is  of  great  importance.  The  following  table  1  shows  figures 
obtained  at  five  factories  in  Wisconsin  where  soft  coal  was  burned 
and  five  others  where  wood  was  used. 


DAILY   FUEL    USED   AT   SEVERAL   CREAMERIES 


Pounds  of  Milk 
Skimmed 
per  Day 


3,5oo 
8.000 
23,000 
6.000 
5,3oo 


Pounds  of 

Soft  Coal 

Burned 


500 
400 
1000 
300 
500 


Cost  of  Coal 

per 

'"on 

$3 

55 

3 

00 

4 

05 

3 

50 

3 

15 

Estimated  Cost 

per 

Day 

• 

$0 

90 

0 

60 

2 

00 

0 

50 

0 

80 

Pounds  of  Milk 

Skimmed 

per  Day 

2,000 

3,400 

6,500 

3,800 

4,5oo 

Cords  of  Wood 
Burned 


Price  per  Cord 


$1-25 
2.25 
1  25 
2.25 
1.80 


Estimated  Cost 
per  Day 


$0.32 

o.37 
0.32 

o.37 
0.60 


These  are  the  best  obtainable  figures  of  comparison  under 
creamery  conditions. 

If  wood  is  burned  the  dryness  of  it  is  an  important  considera- 
tion. If  the  wood  is  wet  its  power  of  producing  heat  is  greatly 
lessened,  as  a  certain  amount  of  heat  is  used  in  evaporating  the 
water  in  the  wood.  Air-dry  wood  will  contain  from  12  per  cent 
to  25  per  cent  water.  The  quality  of  coal  is  another  variable 
factor.  In  general,  and  from  the  table  which  follows,  it  might  be 
said  that  2  J  pounds  of  wood  are  equal  to  1  pound  of  lump  coal. 


Farrington  in  Hoard's  Dairyman. 


DAILY  WEIGHING  OF  COAL  USED  383 

The  following  comparative  table  is  given  by  Kent: 

Hickory  or  hard  maple,  weight  per  cord  4500  lbs.  =  1800  to  2000  lbs.  qf_cqal. 

White  oak,  weight  per  cord  3850  lbs.  =  1540  to  1715  lbs.  of  coal. 

Poplar,  chestnut  and  cedar,  weight  per  cord  2350  lbs.  =  940  to  1050  lbs.  of  coal. 
Pine,  weight  per  cord  2000  lbs.  =  800  to    925  lbs.  of  coal. 

Whether  a  creamery  can  economically  use  slack  or  lump  coal 
is  another  question  worth  considering.  Slack  coal  is  used  very 
little  in  local  creameries,  mainly  because  it  is  more  difficult  to  use 
in  firing.  Usually  help  is  scarce,  and  coal  which  requires  less 
attention  in  firing  is  preferred.  In  the  second  place  slack  coal  is 
subject  to  spontaneous  combustion  and  likely  to  set  buildings 
afire.  Some,  if  not  all  insurance  companies,  discriminate  against 
creameries  using  slack  coal  as  fuel.  Thirdly,  special  grates 
(rocking  grates)  are  essential  to  get  best  results  from  using  slack. 
Fourthly,  slack  coal  is  dirty  and  the  dust  from  it  will  lodge  all 
over  in  the  boiler  and  engine  room. 

Slack  coal,  where  conditions  are  at  all  favorable  for  its  use, 
is,  as  a  rule,  cheap  to  burn.  According  to  experimental  data, 
1  pound  of  slack  coal  will  produce  about  4  pounds  of  steam, 
and  1  pound  of  lump  coal  will  produce  about  6  pounds  of  steam. 
The  price  of  the  two  will  vary,  but  usually  the  relation  is,  slack 
coal,  $1.25  per  ton;  lump  coal,  $3.25  per  ton.  If  1  pound  of  lump 
coal  produces  6  pounds  of  steam,  a  ton  will  produce  12, coo 
pounds.  If  1  pound  of  slack  coa]  produces  4  pounds  of  steam, 
to  produce  12,000  pounds  will  require  2992  pounds  of  slack  coal, 
which  would  cost  $1.87.  The  difference  in  producing  12,000 
pounds  of  steam  in  favor  of  slack  coal  would  then  be  $1.38. 

Daily  Weighing  of  Coal  Used. — The  advantage  of  daily 
weighing  of  coal  used  in  creameries  cannot  be  too  strongly 
emphasized.  That  business  phase  of  creamery  work  has  been 
much  neglected  in  the  past.  If  the  coal  used  daily  is  not  weighed, 
a  serious  loss  or  leak  may  continue  without  detection.  Firing 
the  boiler  is  a  daily  occurrence,  and  if  a  small  loss  occurs,  the  total 
loss  at  the  end  of  the  year  will  cut  short  the  profits. 

The  weighing  can  be  done  conveniently  by  fitting  a  box 
similar  in  shape  to  an  enlarged  flat-sided  curd  pail  on  a  pair  of 
platform  scales.     After  the  scale  and  box  have  been  purchased 


384  ECONOMIC  OPERATION  OF  CREAMERY 

there  are  no  additional  expenses  and  very  little    extra  labor 
required. 

Cleaning  the  Boiler. — The  amount  of  coal  used  will  vary  with 
several  factors,  viz.,  cleanliness  of  flues,  sediment  in  the  boiler, 
condition  of  fire,  kind  of  boiler,  steam  leaks,  pipe  insulation,  etc. 
The  two  first  factors  are  frequently  neglected.  The  flues  should 
be  cleaned  every  morning  before  the  day's  run.  The  inside  of 
the  boiler  should  be  kept  clean.  Heavy  scale  on  the  inside  of  the 
boiler  and  flues,  and  heavy  sediments  on  the  bottom  of  the  boiler, 
should  never  be  allowed  to  accumulate.  Some  water  naturally 
contains  a  large  amount  of  minerals  and  leaves  a  heavy  deposit 
in  the  boiler.  The  operator  should  learn  to  know  the  condition 
of  the  water,  and  the  frequency  of  cleaning  the  inside  of  £he  boiler 
should  be  governed  accordingly.  One  cleaning  per  month  is 
sufficient  with  most  water.  In  some  instances,  one  cleaning  per 
week  is  necessary. 

The  collection  of  scale  and  sediment  within  the  boiler  affects 
the  economic  operation  in  at  least  three  ways:  First,  more  fuel 
is  needed;  second,  the  boiler  itself  is  likely  to  warp;  third, 
foaming  or  priming  of  the  boiler  is  likely  to  occur.  If  scale 
clings  to  the  flues  when  washed,  it  may  be  removed  by  putting 
some  sal-soda  and  water  into  the  boiler  and  boiling  for  several 
hours.  Some  use  a  boiler  compound  for  preventing  scales. 
This  is  not  necessary  nor  to  be  recommended  except  in  extreme 
cases  where  the  mineral  content  of  the  water  is  very  high.  The 
boiler  should  be  frequently  blown  off  at  low  pressure. 

Priming  of  Boilers. — When  considerable  water  passes  over 
with  the  steam  the  boiler  is  said  to  be  priming.  This  water  in  the 
steam  interferes  with  the  running  of  the  engine,  filling  the  engine- 
cylinder  and  resulting  in  broken  piston  or  cylinder-head.  The 
engine  jerks  and  thumps  to  such  an  extent  that  there  is  danger  of 
breaking  other  parts  of  the  machinery. 

The  foaming  or  priming  of  boilers  is  due  chiefly  to: 
i .  Too  much  water  in  the  boiler. 

2.  Working  the  boiler  beyond  its  capacity. 

3.  Allowing  mud  and  minerals  to  accumulate  in  boiler. 

4.  Using  too  much  of  certain  boiler  compounds. 


THE  INJECTOR  385 

5.  Using  water  which  naturally  contains  a  large  percentage 
of  certain  minerals  conducive  to  foaming. 
The  Injector. — The  injector  on  the  boiler  frequently  causes 
the  operator  some  annoyance  by  refusing  to  work.     The  common 
causes  of  this  are: 

1.  Too  low  boiler  steam  pressure. 

2.  Steam  obtained  from  a  pipe  already  supplying  steam  for 

other  purposes. 

3.  Leaks  in  suction  pipe  due  to  shortage  of  supply  pipe 

or  holes  in  pipe. 

4.  Too  hot  supply  water. 

5.  Scale  in  injector,  preventing  proper  working  of  valves. 

6.  Steam  containing  too  much  water. 

Oil-separators. — Considerable  saving  can  be  accomplished  in 
a  creamery  if  the  exhaust  steam  is  utilized.  This  steam  may  be 
used  for  pasteurizing  the  skim-milk,  for  heating  the  milk  previous 
to  separation,  for  heating  the  creamery,  and  for  heating  the  water 
for  the  boiler. 

The  exhaust  steam  contains  considerable  oil  and  should  be 
purified  before  it  is  used  for  any  other  purposes.  Several  forms 
of  steam  purifiers  are  on  the  market.  They  are  simple,  inexpen- 
sive, and  can  be  attached  to  the  exhaust-pipe  of  any  engine. 

All  steam  and  water  pipes  should  be  carefully  drained  in  the 
winter  to  prevent  freezing. 

Belt,  Pulley  and  Speed  Calculation. — The  length  of  a  belt 
may  best  be  determined  by  measuring  over  the  two  pulleys 
with  a  tape  or  a  string. 

To  calculate  the  size  of  a  drive  pulley  when  the  speed  of  it  is 
known  the  diameter  of  the  driver  pulley  is  multiplied  by  its  speed 
and  the  product  divided  by  the  speed  of  the  driven  pulley,  the 
quotient  will  be  the  diameter  or  size  of  the  needed  pulley. 

To  calculate  the  speed  of  a  driven  pulley,  multiply  the 
diameter  by  the  speed  of  the  driver  pulley  and  divide  the  product 
by  the  diameter  of  the  driven  pulley;  the  quotient  is  the  speed  or 
number  of  revolutions  per  minute. 


APPENDIX 


LEGAL    STANDARDS    FOR    DAIRY    PRODUCTS,    1920 


States 


Alabama 

California 

Colorado 

Connecticut 

District  Columbia .  . 

Delaware 

Florida 

Georgia 

Hawaii 

Idaho 

Illinois 

Indiana 

Iowa 

Kansas 

Kentucky 

Louisiana 

Maine 

Maryland 

Massachusetts 

Michigan 


Minnesota 

Missouri 

Montana 

Nebraska 

New  Hampshire. 

New  Jersey 

New  Mexico.  .  .  . 

New  York 

North  Carolina.. 
North  Dakota .  . 

Ohio 

Oklahoma 

Oregon 

Pennsylvania.  .  . 

Porto  Rico 

Rhode  Island  .  .  . 
South  Carolina. . 
South  Dakota. .  . 

Tennessee 

Texas 

Utah 

Vermont 

Virginia 

Washington 

Wisconsin 

Wyoming 


Milk 


Total 
Solids 


7  5 


12 

II.  5 
II 


II. 75 

12.5 

12.15 

12.5 


12 
12 

II. 5 

12 
12 

12.5 
12.2 

None; 
12 
12 


Solids 
Not 
Fat 


% 

8.5 
8.5 
8.5 
9 


8.5 
8.5 


8.5 
8.5 
8.5 


Fat 


% 

3 

3-25 
3-25 
35 


3-25 

3 

3 

3 

325 

3 


8.5 


9 
mumci 


.25 
•  25 

5 
.25 

5 

35 


3-5 
325 
3 
3 


3 

32 

3 

3 

3 

32 

pal  con 

3 

2.5 

325 

325 

325 

3-2 

4 

325 

3-25 

3 

34 


Skim- 
milk 


Total 
Solids 


% 

None; 

925 

9-25 


>!'» 


3 

one; 

None ; 

9-25 


9-25 
9-25 
9-25 


9-25 
8.00 


9-3 

Sp.gr. 

32 

9-25 


9 
None; 
9-25 


trol 


None; 
9-25 


9-25 

9-3 

9 


Cream 


Fat 


% 

munici 

18 

18 

20 
munici 
munici 

18 

"i8- 
18 
18 
15 

18 
18 


15 

}•« 

20 
18 
15 
18 
18 
16 
munici 

18 
15 


munici 
18 
18 


Butter 


Whole- 
ilk 
Cheese 


Fat 


% 
pal  con 
80 
82.5 

283 
pal  con 
pal  con 

82.5 

82.5 
82. s 
82.5 
80 

82.5 
82.5 


80 
82.5 


80 
pal  con 

82:5 

80 


pal  con 
80 
82.5 

80 

82.5 

82:5 
80 


Condensed 
Milk 


Total     Total 
Solids  Solids 


trol 
130 
35 


trol 
trol 
50 

130' 
50 


trol 
4'5o' 


trol 
4  50 
4  50 


;5o 

x30 

50 

1  20 


24-5 
28 


28 


Fat 


% 


7-7 

7-7 


7 

7-7 
7-7 
7-7 


7-7 

7-7 


3 

7-7 


7 
4-5 


7-7 
7-7 


7 
7-7 


1  Per  cent  of  fat. 

2  Not  over  12  per  cent  water  or  5  per  cent  salt. 

3  Proportion  of  fat  to  total  solids  must  be  the  same  as  in  the  crude  milk. 

4  Per  cent  of  fat  in  total  solids. 
'  May  and  June,  12. 

387 


388  APPENDIX 

METRIC   SYSTEM1 

METRIC  SYSTEM  OF  WEIGHTS  AND  MEASURES  AND 
TABLES  FOR  THE  CONVERSION  OF  METRIC 
WEIGHTS  AND  MEASURES  INTO  CUSTOMARY 
UNITED  STATES  EQUIVALENTS  AND  THE  REVERSE. 

In  the  metric  system  the  meter  is  the  base  of  all  weights  and 
measures. 

The  meter  was  intended  to  be,  and  is  very  nearly,  one  ten- 
millionth  part  of  the  distance  measured  on  a  meridian  of  the 
earth  from  the  equator  to  the  pole,  and  equals  about  39.37 
inches  or  nearly  3  feet  3!  inches. 

The  meter  is  the  primary  unit  of  length. 

Upon  the  meter  are  based  the  following  primary  units:  the 
square  meter,  the  are,  the  cubic  meter  or  stere,  the  liter,  and 
the  gram. 

The  square  meter  is  the  unit  of  measure  for  small  surfaces; 
as  the  surface  of  a  floor,  table,  etc. 

The  are  is  the  unit  of  land  measure;  this  is  a  square  whose 
side  is  10  meters  in  length,  and  which  contains  100  square  meters. 

The  cubic  meter  or  stere  is  the  unit  of  volume;  this  is  a 
cube  whose  edge  is  1  meter  in  length. 

The  liter  is  the  unit  of  capacity;  this  is  the  capacity  of  a 
cube  whose  edge  is  one-tenth  of  a  meter  in  length. 

The  gram  is  the  unit  of  weight;  this  is  the  weight  of  distilled 
water  contained  in  a  cube  whose  edge  is  the  one-hundredth  part 
of  a  meter;  a  gram  is  therefore  the  one- thousandth  part  of  a 
kilogram,  and  the  one-millionth  part  of  a  metric  ton. 

^rom  The  American  Chamber  of  Commerce. 


APPENDIX 


389 


MEASURES  OF  LENGTH 


Metric  Denominations  and  Values 

Equivalents  inDenominations  in  Use 

Myriameter 

10,000  meters 
1,000  meters 
100  meters 
10  meters 
1  meter 
.  1  meter 
.01  meter 
.001  meter 

6.2137  miles 
.62137  mle,  or  3,280  ft.  10  in. 
328  feet  1  inch 
393 . 7  inches 
39.37  inches 
3.937  inches 
.3937  inch 
. 0394  inch 

Kilometer 

Hectometer 

Dekameter 

Meter 

Decimeter 

Centimeter 

Millimeter 

MEASURES   OF   SURFACE 


Metric  Denominations  and  Values 

Equivalents  in  Denominations  in  Use 

Hectare 

Are 

Centare 

10,000  square  meters 

100  square  meters 

1  square  meter 

2.471  acres 
119. 6  square  yards 
1550  square  inches 

MEASURES  OF   CAPACITY 


Metric  Denominations  and  Values 

Equivalent  in  Denominations  in 
Use 

Names 

No.  of 

Liters 

Cubic  Measure 

Dry  Measure 

Liquid  or  Wine 
Measure 

Kiloliter  or  stere .  . 

Hectoliter 

Dekaliter 

Liter 

1000 

100 

10 

1 

.1 
.01 
.001 

1  cubic  meter 
.  1  cubic  meter 
10  cu.  decimeters 
1  cu.  decimeter 

.1  cu.  decimeter 
10  cu.  centimeters 
1  cu  centimeter 

1 .  308  cu.  yds. 
2  bush.  3.35  pks. 
9 .  08  quarts 

.  908  quart 
6. 1022  cu.  ins. 

.6102CU.  in. 

.061  cu.  in. 

264 . 1 7  gals. 
26.417  gals. 
2.6417  gals. 
1.0567  qts. 

.845  gill 
.338fl.oz. 
.  27  fl.  dram 

Deciliter 

Centiliter 

Milliliter 

390 


APPENDIX 


WEIGHTS 


Metric  Denominations  and  Values 

Equivalents  in 

Denominations  in 

Use 

Names 

Number  of 
Grams 

Weight  of  What 

Quantity  of  Water  at 

Maximum  Density 

Avoirdupois 
Weight 

Metric  ton 

1,000,000 
100,000 
10.000 
1,000 
100 
10 
1 
.1 
.01 
.001 

1  cubic  meter 

1  hectoliter 

1  dekaliter 

1  liter 

1  deciliter 
10  cubic  centimeters 

1  cubic  cent  meter 
.  1  cubic  ecntimeter 
10  cubic  millimeters 

1  cubic  millimeter 

2204.6  pounds 
220.46  pounds 
22.046  pounds 
2 .  2046  pounds 
3.52*74  ounces 
.3527  ounce 
15.432  grains 
1.5432  grains 
.1543  grain 
.0154  grain 

Quintal 

Myriagram 

Kilogram  or  kilo 

Hectogram 

Dekagram , . . 

Gram 

Decigram 

Centigram 

Milligram 

COMMON  MEASURES  AND  WEIGHTS,  WITH  THEIR  METRIC 
EQUIVALENTS 

The  following  are  some  of  the  Measures  in  common  use,  with  their  equivalents 
in  measures  of  the  Metric  System 


Common 

Common 

Measures 

Equivalents 

Measures 

Equivalents 

1  inch 

2 .  54  centimeters 

1  cord 

3 .  624  steres 

1  foot 

.3048  meter 

1  liquid  quart 

.9465  liter 

1  yard 

.9144  meter 

1  gallon 

3.86  liters 

1  rod 

5.029  meters 

1  dry  quart 

1 .  101  liters 

1  mile 

1 .  6093  kilometers 

1  peck 

8. 81 1  liters 

1  square  inch 

6.452  sq.  centimeters 

1  bushel 

35 .  24  liters 

1  square  foot 

.0929  square  meter 

1  ounce  av'd'p 

28.35  grams 

1  square  yard 

.8361  square  meter 

1  pound  av'd'p 

.  4536  kilogram 

1  square  rod 

25 .  29  square  meters 

1  ton  (2000  lbs.) 

.9072  met.  ton 

1  acre 

.4047  hectare 

1  ton  (2240  lbs.) 

1. 01 6  metric  ton 

1  square  mile 

259  hectares 

1  grain  troy 

.  0648  gram 

1  cubic  inch 

16.39  cu.  centimeters 

1  ounce  troy 

31. 104  grams 

1  cubic  foot 

.02832  cubic  meter 

1  pound  troy 

.3732  kilogram 

1  cubic  yard 

.  7646  cubic  meter 

APPENDIX 


391 


TABLE  FOR  THE  CONVERSION  OF  METRIC  WEIGHTS  AND  MEASURES 
TNTO  CUSTOMARY  UNITED  STATES  EQUIVALENTS  AND  THE 
REVERSE. 

From  the  legal  equivalents  are  deduced  the  following  tables  for  converting  United 
States  weights  and  measures : 

METRIC   TO    CUSTOMARY 

Linear  Measure 


Meters  =  Inches 

Meters  =  Feet 

Meters  =  Yards 

Kilometers  =  Miles 

i=   39-37 

1=  3.28087 

1  =  1.093623 

1=0.62137 

2  =     78.74 

2=  6.56174 

2  =  2 

187246 

2  =  1 .  24274 

3  =  Il8.II 

3=  9.84261 

3  =  3 

280869 

3  =  1 .86411 

4=157.48 

4=13.12348 

4  =  4 

374492 

4=2.48548 

5  =  196.85 

5  =  16.40435 

5  =  5 

468175 

5  =  3.10685 

6=236.  22 

6  =  19.68522 

6  =  6 

561738 

6  =  3.  72822 

7=275.59 

7  =  22.96609 

7  =  7 

65536i 

7  =  4-34959 

8  =  314.96 

8=26.  24696 

8  =  8 

748984 

8  =  4.97096 

9  =  354-33 

9=29.52783 

9  =  9 

842607 

9  =  5- 59233 

CUSTOMARY   TO   METRIC 

Linear  Measure 


Inches  =  Centimeters 

Feet  =  Meters 

Yards  =  Meters 

Miles  =  Kilometers 

1=   2.54 

1=0.304798 

1=0.914393 

1=   1.60935 

2=  5.08 

2  =  0.609596 

2  =  1 

828787 

2=  3.21869 

3=   7.62 

3  =  0.914393 

3  =  2 

743179 

3=   4.82804 

4=10. 16 

4=1.  219191 

4  =  3 

657574 

4=   6.43739 

5  =  1 2 . 70 

5  =  1.523989 

5=4 

571966 

5=   8.04674 

6  =  15.24 

6  =  1.828787 

6  =  5 

486358 

6=  9.65608 

7  =  17-78 

7  =  2.133584 

7  =  6 

400753 

7  =  11.26543 

8=20.32 

8  =  2.438382 

8=7 

315148 

8  =  12.87478 

9  =  22.86 

9  =  2.743179 

9  =  8 

229537 

9  =  14.48412 

392 


APPENDIX 


Square  Measure 


Square  Centi- 
meters = 
Square  Inches 


1=0.155 

2  =  0.310 

3  =  0.465 

4  =  0.620 

5  =  o.775 

6  =  0.930 

7  =  1.085 

8  =  1.  240 

9  =  i-395 


Square  Meters 
=  Square  Feet 


1  =  10.  764 

2  =  21.528 

3  =  32.292 

4  =  43-055 

5  =  53.819 

6  =  64.583 

7  =  75-347 

8  =  86.111 

9  =  96.874 


Square  Meters 
=  Square  Yards 


1  = 

2  = 

3  = 

4  = 

5  = 

6  = 

7  = 

8  = 

9  = 


196 
392 
588 

784 

980 

7.176 

8.372 

9- 568 

10. 764 


Cubic  Measure 


Cubic  Meters 
=  Cubic  Feet 


1=  35-3I5 
2=  70.631 
3  =  105.947 
4=141.  262 

5  =  176.584 

6  =  210.899 

7  =  247.209 
8=282.525 
9  =  317.840 


Cubic  Feet 
Cubic  Meters 


1=0.02832 

2  =  0.05663 

3  =  0.08495 

4  =  0. 11326 
5=0.14158 
6=0. 16990 
7=0.19821 
8=0.22653 
9  =  0.25484 


Square  Measure 

Liquid  Measure 

Square  Inches 

=  Square 

Centimeters 

Square  Feet 
=  Square 
Meters 

Square  Yards 
=  Square 
Meters 

Centimeters 
=  Fluid 
Ounces 

Liters  = 
Quarts 

Liters = 
Gallons 

1=   6.452 

2  =  12. 903 

3  =  19-354 
4=25.806 

5  =  32.257 

6  =  38.709 

7  =  45.160 

8  =  51.612 

9  =  58.063 

1=0.09290 

2  =  0.18581 

3  =  0.27871 

4  =  0.37161 
5=0.46452 
6  =  0.55742 
7=0.65032 
8=0.74323 
9=0.83613 

1=0.836 

2  =  1.672 

3  =  2 . 508 

4  =  3-344 

5  =  4.181 

6  =  5.017 

7  =  5-853 

8  =  6.689 

9  =  7-525 

1=0.338 
2=0.676 
3  =  1.014 
4=i-352 

5  =  1.691 

6  =  2.029 

7  =  2.368 

8  =  2. 706 

9  =  3-043 

1  =  1.0567 

2  =  2.1134 

3  =  3.1700 

4  =  4.2267 

5  =  5- 2834 

6  =  6. 3401 

7  =  7.3968 

8  =  8.4534 

9  =  9.5101 

1=0.26417 

2  =  0.52834 

3  =  0.79251 
4=1.05668 

5  =  1.32085 

6  =  1.58502 

7  =  1.84919 

8  =  2.11336 

9  =  2-37753 

Dry  Measure 


Hectoliters  = 
Bushels 


1=  2.8375 
2=  5-6750 
3=  8.5125 
4=11.3500 

5  =  14.1875 

6  =  17.0250 

7  =  19.8625 

8  =  22.  7000 

9  =  25-5375 


Bushels  = 
Hectoliters 


1=0.35242 
2=0.70485 
3  =  1.05727 
4=1. 40969 

5  =  1.  76211 

6  =  2.11454 

7  =  2. 46696 

8  =  2.81938 

9  =  3.17181 


Liquid  Measure 


Fluid  Ounces : 
Centiliters 


1=  2.957 
2=  5-915 
3=  8.872 
4=11.830 

5  =  i4-787 

6  =  17-744 

7  =  20.702 
8=23.659 
9=26.616 


Quarts  = 
Liters 


1=0.94636 

2  =  1.89272 

3  =  2.83908 

4  =  3  38544 
5=4.33180 

6  =  5.67816 

7  =  6.62452 
8=7.57088 
9  =  8.51724 


Gallons  = 
Liters 


1=  3-78544 
2=  7-57o88 
3  =  11.35632 
4=15.14176 

5  =  18.92720 

6  =  22.  71264 

7  =  26 . 49808 

8  =  30.28352 

9  =  34 . 06896 


APPENDIX 
(Weight  Avoirdupois) 


393 


Centigrams = 
Grains 

Kilograms  = 
Ounces  Avoirdu- 
pois 

Kilograms = 
Pounds  Avoirdu- 
pois 

Metric  Tons  =  Long 
Tons 

i  =0.1543 

1=  35-274 

1=   2.20462 

1=0.9842 

2=0.3086 

2=   70.548 

2=  4.40924 

2  =  1. 9684 

3=0.4630 

3  =  105.822 

3=  6.61386 

3  =  2.9526 

4=0.6173 

4=141.096 

4=  8.81849 

4=3.9368 

5=0.7716 

5  =  176.370 

5  =  11.02311 

5  =  4.9210 

6=0.9259 

6  =  211.644 

6  =  13.22773 

6  =  5.9052 

7  =  1.0803 

7  =  246.918 

7  =  15.43235 

7=6.8894 

8=1.2346 

8  =  282. 192 

8=17.63697 

8  =  7.8736 

9=13889 

9  =  317.466 

9  =  19.84159 

9=8.8578 

Grains  =  Centi- 

Ounces Avoirdu- 

Pounds Avoirdu- 

Long Tons  =  Metric 

grams 

pois  =  Grams 

pois  =  Kilograms 

Tons 

1=  6.4799 

1=   28.3495 

i=o.45359 

1  =  1.0161 

2  =  12 

9598 

2=  56.6991 

2=0.90919 

2  =  2.0321 

3  =  i9 

4397 

3=  85.0486 

3  =  1.36078 

3  =  3.0482 

4=25 

9196 

4=113.3981 

4=1.81437 

4=4.0642 

5=32 

3995 

5  =  141.7476 

5  =  2.26796 

5  =  5.0803 

6=38 

8793 

6  =  170.0972 

6  =  2.72156 

6  =  6. 0963 

7  =  45 

3592 

7  =  198.4467 

7  =  3i75i5 

7  =  7.1124 

8  =  51 

8391 

8  =  226.7962 

8  =  3.62874 

8  =  8.1284 

9  =  58 

3190 

9  =  255.1457 

9  =  4.08233 

9  =  9.1445 

INDEX 


PAGE 

Abnormal  milk 65 

Acid,  butryic,  capric,  caprylic,  myristic,  oleic,  palmitic,  stearic 16 

carbonic,  hydrochloric,  phosphoric,  sulphuric 20 

citric 22 

lactic 19 

salicvlic 127 

sulphuric 98 

tests 94,  222,  223 

Acidity  of  milk 94 

of  ripened  cream  in  relation  to  richness  of  cream 221,  224 

of  starters 237 

tests  for 222,  223 

Adhesion  of  milk 37 

Albumen  in  milk 18 

Albuminoids  in  milk 16 

Alkali  of  various  strengths  for  measuring  acid  in  milk  and  cream 94,  221 

American  Association  Test  for  buttermilk  and  skim-milk 103 

Amphoteric  reaction  of  milk ^ 

Antiseptics 59 

Ash  in  Milk '. 19 

Babcock  test  for  fat 97 

causes  and  remedies  for  common  defects  in  clearness  of  fat 

in , 100 

Bacteria  in  milk,  aroma  and  flavor  producing 215 

as  a  cause  of  deterioration  of  butter. 13 

classification  of 61 

conditions  favoring  development  of 55 

desirable  and  undesirable  in  cream  ripening 217 

kinds  of  germs  found  in  milk 60 

number  of,  in  milk 62 

size  and  shape  of 55 

sources  of 62 

unfavorable  conditions  for 58 

Belt,  pu'ley  and  speed  calculation 385 

Boiler,  cleaning  of 384 

priming  of 384 

firing 381 

wood  or  coal  for 382 

395 


396  INDEX 

Breeds,  composition  of  milk  from  various 75 

Brine,,  salting  butter  with 287 

soaking  tubs  in 300 

Butter,,  appearance  or  style  of 342 

classification  and  grades  of,  as  outlined  by  N.  Y.  and  Chicago  Mercan- 
tile Exchanges 342,  347 

color  of 253,  341 

composition  of 309 

cost  of  manufacturing 297 

exportation  of 350 

flavor  of 341 

for  storage 357,  360 

judging  and  grading  of 340 

keeping  in  creameries 296 

making  of,  on  farm 180 

mottled,  causes  and  remedy * 279 

package,  style  of 294 

packing  of 294 

preparing  for  market 294 

printing  of 299 

saltiness  of 342 

storing  in  creameries 296 

tests  for  fat  in 107 

texture  or  body  of 341 

treatment  of 300 

washing,  and  kind  of  wash-water 263,  265 

working  of 291,  360 

Butter-making,  History  of 1 

Buttermilk,  test  of 101,  103 

removal  of . . 263 

Butyrin 13 

Calculation  of  amoui,t  of  salt  to  add  to  butter 272 

average  per  cent  fat 131 

churn  yield 135 

cream-raising  coefficient 140 

dividends. . 137 

overrun 133 

solids  in  milk 35 

Cans,  starter 238 

washing  of 1 25 

Care  of  cream  on  farm 1 76 

Casein  in  milk,  condition  of 17 

Centrifugal  separation  of  cream 154 

Churn,  keeping  in  good  condition 260 

Churn  yield,  calculation  of 135 

Churned  milk,  sampling 122 


INDEX  397 

PAGE 

Churning,  amount  for  a 247 

color 253 

conditions  affecting 240 

definition  of 239 

degree  of  ripeness 248 

difficult,  causes  and  remedy  for. ..." 258 

mixed,  sweet,  and  sour  cream 258 

nature  of  agitation  for 249 

richness  of  cream  for 245 

size  of  globules 252 

straining  of  cream  previous  to 253 

temperature 240 

when  to  stop 255 

Citric  acid  in  milk 22 

Cold  storage 352 

benefits  of..  .  . 353 

cost  of 355 

history  of 352 

mechanical  refrigeration 353,  363,  375 

Cold  storage  butter,  should  it  be  branded 356 

Color,  butter 253,  341 

Coloring  matter  in  milk 22,  32 

Commercial  starters 227 

preparation  and  use  of 230 

Composite  samples 127 

arrangement  and  care  of 128,  129 

preservatives  for 127 

sampling  apparatus  for .  122 

Composition,  of  butter 309 

acts  and  rulings  as  to 309 

analysis  thirty  years  ago 315 

of  colostrum  milk 65 

compounds  for  increasing  yield 310 

control  of  moisture 312 

of  dairy  salts 278 

different  kinds  of  milk 5 

need  for  regulations 311 

of  salty  milk v 66 

separator  slime 166 

tuberculous  n  ilk 73 

Continuous  method  of  pasteurization 208 

"  Cooley "  method  of  cream  separation 150 

Cooling  facilities,  for  creameries 362 

cooling  systems 362 

mechanical  refrigeration 353,  363,  37$ 

natural  ice 365 


398  INDEX 

PAGE 

Cows,  breeds  of 75 

Cream,  acidity  of,  for  churning 224 

care  of,  on  farm 176 

effect  of  cleanliness  on  quality  of 1 76 

grading  of 93 

methods  of  disposing  of 1 79 

neutralization  of 184 

pasteurization  of 201 

sour 189 

ripening  of 215 

sampling  of 118 

Creamery  sewage  disposal 299, 300 

Curdy  specks  in  butter 285 


Deep-setting  system  of  cream  separation 150 

Defe<  ts  found  in  butter 323 

advance  in  lactation 329 

cheesy  flavor 324 

faulty  factory  conditions 325 

feed  flavors 327 

fishy 336 

flat  or  insipid  flavor 323 

flavors  by  absorption 324 

garlic 327 

metallic  flavor 335 

sour  flavor 325 

stable  flavors 324 

tallowy  flavor 332 

Difficult  churning,  causes  and  remedy 258 

Dilution,  effect  of,  on  creaming 153 

Disinfectants r 59 

Electricity,  effect  of,  on  germs  in  milk 64 

Enzymes  in  milk 22,  54 

classification 54 

effect  of  heat  on 41 

tests  for : 42,  201 

Export  butter 350 

Farrington  test * 223 

Fat,  in  butter 309 

milk 8 

composition  of 15 

condition  of n 

effects  of  environment 80 

heat  on 42 

various  feeds  on  composition  of 242 


INDEX  399 

PAGE 

Fat,  in  milk  glycerides  of 10 

glycerine  in 15 

melting-point  of 10,  14 

membrane  enveloping  fat  globules 11 

microscopical  appearance  of 9 

non-volatile 14 

paying  for,  as  compared  with  fat  in  cream 143 

properties  of 10 

separation  of 149 

size  of  globules 8 

testing  for 98,  99,  103,  107 

volatile 13 

Feeds,  effects  on  milk 79 

Fermentations,  detection  of 67, 94 

various  kinds  of 67,  71,  73 

Ferments  in  milk,  classification  of  enzymes 54 

favorable  and  unfavora1  le  conditions  for 55,  58 

Fibrin 22 

Filtration  of  water 266 

methods  and  effects  of 266,  269,  270 

Flavors  of  butter 323 

milk 20,  32,  40 

Food  for  bacteria 55 

Formula  for  calculating  churn  yield 135 

cream-raising  coefficient 140 

dividends 137 

overrun 133 

solids  in  milk 35 

Frozen  milk,  effects  of  freezing 1 23 


Galactase  in  milk 22 

Garlic,  removal  of  flavor 327 

eradication  of 328 

Gases  in  milk,  eliminating 21 

kinds  and  sources  of 20 

Gerber  fermentation  test r  < 95 

Glassware  for  Babcock  test 99 

Grading  milk  and  cream 92 

Gravity  separation,  different  systerr  s  of , 35,  49 

Gritty  butter , 278 


Heat,  effects  of,  on  properties  of  milk 38, 96 

Heating  milk  previous  to  skimming , 145 

Hydraulic  method  of  separation 153 

Hydrogen  peroxide 202 


400  INDEX 

PAGE 

Ice,  for  cooling  cream 3  74 

refrigeration 365 

Injector 385 

Judging  and  grading  butter 340 

classification 342 

Chicago 347 

New  York 342 

export  butter 350 

manner  of  judging • .  341 

standard  for 340 

Keeping  property  of  butter 188, 360 

effect  of  salt  on 273 

Lactation  period,  effect  of,  on  milk  and  fat ? 78 

Lactochrome  in  milk 22 

Lactometer,  comparison  of  scales  on 35 

use  of 33,97 

Lecithin  in  milk 22 

Lime,  its  use  in  creameries 261 

Mammary  gland,,  description  of 23 

inflammation  of 30 

Mann's  test 222 

Mechanical  refrigeration 353,  363,  375 

Membrane  enveloping  fat  globules n 

Mercantile  Exchange,  New  York  and  Chicago  grades  of  butter 342,  347 

Metric  system  of  weights  and  measures 388 

Milk,  abnormal 65 

appportioning  skimmed 124 

bitter 69 

bloody 67 

blue  and  yellow 68 

classification  of 3 

colostrum 65 

composition 4 

of,  from  different  animals 5 

definition  of 3 

effects  of  thunder-storms  on  souring  of 64 

fat  in  skimmed 150 

fever 30 

from  barren  and  spayed  cows 72 

from  cows  a  long  time  in  milk 71 

grading  of 92 

necessity  of  good 117 

properties  of,  physical  and  chemical 32 


INDEX  401 

PAGE 

Milk,  ropy 68 

salty 66 

sampling  of 118 

frozen,  cl  uned,  aid  sour 122, 123 

secretion  of,  conditions  affecting 28 

theories 26 

from  sick  cows 72 

specific  gravity  of 33 

specific  heat  of 38 

variation  in  quality  of,  and  causes 74 

water  of 6 

Milk  and  its  products  as  foods 43 

biological  classification 45 

ash 46 

proteins 46 

unidentified   substance 

in  n  ilk  fat 47 

chemical  classification. .  . ;'. 44 

Milking,  frequency  of 75 

manner  of 76 

Moisture  control 312 

factors  that  aid  in 318 

tests  of  butter 203 

Mold,  in  butter 304 

on  butter 306 

conditions  favorable  to  growth 307 

discolorations 307 

propagation 307 

sources  of 307 

Mottles,,  causes  of,  in  butter 279 

kinds  of 281 

prevention  of 284 

Natural  starters,  preparation  of 226 

Neutralization,  "neutralization"  of  cream 183 

neutralization  of  cream  for  butter-making 184 

neutralization,  principle  of 183 

other  neutralizers 199 

pints  of  lime  mixture  required  to  reduce  acidity  to  .25  per 

cent  (Table) 196 

the  preparation  and  use  of  lime  as  a  neutralizer 192 

Non-volatile  fats 14 

Nuclein  in  milk 22 

Oil  separator 385 

Olein,  effect  of  variation  of,  on  softness  of  butter 14 

Opacity  of  milk ,,,,,, 32 


402  INDEX 


PAGE 

Overrun,  definition  and  calculation  of 133 

factors  governing 133 

what  should  it  be 135 

Packing  butter 294,  360 

kind  and  style  of  package 294 

for  storage 360 

treatment  of  tubs  previous  to 300 

Palmitin 14,15 

Paraffining  of  tubs 302 

Parchment  paper,  treatment  of 304 

Pasteurization,  advantages  of 201,  214 

cost  of 212 

definition 201 

disadvantages  of 214 

good  milk  and  cream  important 204 

methods  of 208 

sanitation 206 

Storch  Test  for 201 

temperatures 202 

Pasteurizers,  durability  and  efficiency 210 

Paying  for  fat  in  cream  as  compared  with  fat  in  milk 143 

Proteids  in  milk,  as  a  cause  of  mottles  in  butter 280 

kinds  of 16 

Quevenne  lactometer 34 

Receiving  milk  and  cream 92 

Richness  of  cream  from  centrifugal  separator 81 

gravity  separation 151 

Ripening  cream,  definition 215 

degree  of  acidity  to  ripen  to 224,  248 

kinds  of  acids  produced  from 215,  217,  229 

mixing  starter  with  cream 221 

objects  of 215 

temperature 220 

tests  for  acidity 221 

Salt,  as  a  cause  of  mottles 279 

composition  of  American  and  Danish 278 

condition  of,  when  added  to  butter 277 

effect  of,  on  keeping  property  of  butter 273 

removal  of  butterrrilk 275 

in  relation  to  water  in  butter 275 

kind  and  condition  of 277 

undissolved,  in  butter 278 

Salt  test,  chemical  changes 288 

features  of •  •• ...... : . : 289 


INDEX  403 

PAGE 

Salt  test,  principle  of 28S 

to  make 290 

Salting  butter,  amounts  of  salt  to  use 272 

effects  of,  on  keeping  property  of  butter 273 

purpose  of 272 

with  brine 287 

Samples,  average 1 30 

composite 127 

Sampling-tube 1 20 

Score-card  for  butter 340 

Sediment  test 116 

Separation,  advantages  of  centrifugal 155 

centrifugal 154 

classification  of  centrifugal  machines 158 

conditions  affecting  completeness  of 161 

effect  of  speed  as  compared  with  diameter  on 164 

factors  governing  richness  of  cream 81 

gravity 35^49 

heating  milk  for 145 

history  and  development  of 155 

process  of  centrifugal 158 

Separators,  farm,  introduction  and  development 168 

objections  to 171 

power  for 1 74 

reasons  for  introducing 168 

thickness  of  cream 172 

Separator  slime,  composition  of 165 

Sewage-disposal  plants,  cuts  of 299,  300 

Shallow-pan  creaming 149 

Skimmed  milk,  apportioning 1 24 

Standards,  legal,  for  butter 317 

dairy  products 387 

Starter  cans 238 

Starters,  amount  to  use 221,  237 

commercial 227 

definition,  history,  and  classification 225,  226 

inoculation • 232 

length  of  time  to  carry . 236 

milk  powders  for 235 

natural 226 

poor 236 

preparation  of 226,  230 

Statements,,  annual 141 

patrons'  monthly 141 

Sterilization 203 

Storch  test 201 

Streaked  butter 281 

Sugar  in  milk 18 


404  INDEX 

PAGE 

Table  showing  effect  of  temperature  on  growth  of  bacteria 56,  57 

fat  and  total  solids  of  milk  from  various  breeds 76 

Taints  in  milk,  eliminating.  .  .  : 21,  40 

sources  of 20 

Temperature,  churning 240 

duration  of 245 

effect  of,  on  bacterial  growth 56,  57 

for  storing  butter 296 

pasteurization 202 

ripening 220 

separation 145 

wash-water 263 

Tests,  acid 94,  221 

fat 97 

in  butter 107 

buttermilk  and  skim-n.ilk 101 

cream 99 

milk 98 

Tests,  fermentation 94 

pasteurized  milk 201 

Total  solids  in  milk,  variation  of 5 

Tubs  and  boxes,  paraffining  of 302 

styles  of 294 

treatment  of .  : 300 

Udder,  external  appearance  of 30 

internal  structure  of 23 

Urea  in  milk 22 

Utensils,  cleaning 1 25, 166 

Variation  of  fat  in  cream,  causes  of 81 

amount  of  water  or  skim  milk  used  to  flush  the  bowl  90 

cream  screw  adjustment 82 

rate  of  inflow 85 

richness  of  milk 83 

speed  of  machine 87 

temperature  of  milk .  88 

Variation  of  fat  in  milk,  causes  of 74 

advance  in  lactation 78 

age  of  cow 78 

breed  of  cows 75 

condition  of  cow 80 

environment 80 

feed  of  cows 79 

fore  and  after  milk 77 

individuality  of  cows 74 

manner  of  milking 76 

time  between  milkings 75 


INDEX  405 

PAGE 

Viscogen,  use  of 39 

Viscosity  of  milk .  . .  37,  39 

restoration  of ~T.    "39 

Vitamines 47 

Volatile  fats , ,     13 

Washing  butter,  kind  of  wash-water  for 265 

purpose  of 263 

Washing  cans 125 

Water  in  butter,  condition  of 257 

control  of 312 

Water,  filtration 266 

in  relation  to  salt  in  butter 275 

methods  of  purifying 266 

pasteurization 266 

Wisconsin  curd  test 95 

Working  of  butter,  for  storage 360 

objects  and  effects  of 291 


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